ANDREW PIERCE: Meet the second most powerful man in Britain: He cut his political teeth purging extremists on both the Left and Right. Now Starmer's 'friend and enforcer' is at the heart of No 10

The pictures wouldn't look out of place in Country Life magazine. An ostentatious chandelier, a three-oven Aga in the flagstone-floor kitchen, while the stylish study features floor-to-ceiling custom bookcases.

The £750,000 sandstone mansion, set in glorious Lanarkshire countryside, even comes with stable blocks. Welcome to the home of Morgan McSweeney — now the second most powerful man in the country.

Tony Blair employed the thuggish Alastair Campbell as his chief spin doctor, while Peter (now Lord) Mandelson revelled in his nickname 'The Prince of Darkness'.

Yet McSweeney, Starmer's new 'head of political strategy', stands to be more influential than either of his Downing Street predecessors. As one senior party figure puts it: 'No unelected figure in postwar Labour history wields as much power as Morgan McSweeney.'

The redhead Irishman, who was the brains behind Starmer's triumphant election victory, also helped to install Starmer as leader and purge the party of the far-Left. Ruthless and calculating, McSweeney now has significant control over messaging and policy.

Though he rarely credits him publicly, Starmer has McSweeney to thank more than anyone for making it to Downing Street. Yet even many Labour MPs have probably never met McSweeney, who at party conferences shuns the bars and spends most of his time in the leader's hotel suite.

The £750,000 sandstone mansion, set in glorious Lanarkshire countryside, even comes with stable blocks. Welcome to the home of Morgan McSweeney (pictured) ¿ now the second most powerful man in the country

The £750,000 sandstone mansion, set in glorious Lanarkshire countryside, even comes with stable blocks. Welcome to the home of Morgan McSweeney (pictured) — now the second most powerful man in the country

Yet McSweeney, Starmer's new 'head of political strategy', stands to be more influential than either of his Downing Street predecessors

Yet McSweeney, Starmer's new 'head of political strategy', stands to be more influential than either of his Downing Street predecessors

and policy. Though he rarely credits him publicly, Starmer has McSweeney to thank more than anyone for making it to Downing Street

and policy. Though he rarely credits him publicly, Starmer has McSweeney to thank more than anyone for making it to Downing Street

The anonymity suits the workaholic McSweeney, who was invariably at his desk at Labour's South London HQ by 6.30am. He will not show any signs of slowing down now that Labour is in government. And from his new desk in No 10 he will be closely observing exactly who visits Starmer.

When key aides lined Downing Street to welcome the incoming Prime Minister, McSweeney was already inside. Starmer made a beeline for his adviser — who was suited and booted rather than casually dressed in his customary jeans — and made sure his was one of the first hands he shook.

McSweeney's word is law. One top party figure tells me: 'Every minister defers to him. He is Keir Starmer's friend, confidant and enforcer. There is no higher praise at HQ than: 'Morgan loves it.'

Yet perhaps not from all quarters. Relations between McSweeney and Sue Gray, the former 'impartial' civil servant whose excoriating Partygate report triggered the ultimate downfall of Labour's nemesis Boris Johnson, are said to be prickly. Gray is now the Prime Minister's chief of staff — another vital Downing Street role.

One source says: 'Keir needs Morgan by his side. Morgan's desk will be outside the No 10 study, and he will be in and out of Keir's office more than Sue. But look out for the fireworks.'

So who is Morgan McSweeney — and what does he plan to do with the power he now wields?

The 47-year-old was brought up in Macroom in County Cork, and still speaks with a soft Irish lilt. His grandfather, Michael, won a medal from the IRA for his service during the 1916 war of independence from Britain.

His father, Tom, was an accountant and his mother, Carmel, worked in an office. Yet politics runs in the family: cousin Clare Mungovan was a special adviser to Taoiseach Leo Varadkar.

In the summer of 1994, when Tony Blair became Labour leader, McSweeney, then 17, left Macroom for a new life in London.

Blair knew he had to modernise the Labour Party, which had lost four successive elections, and McSweeney watched with interest.

In the summer of 1994, when Tony Blair (pictured) became Labour leader, McSweeney, then 17, left Macroom for a new life in London

In the summer of 1994, when Tony Blair (pictured) became Labour leader, McSweeney, then 17, left Macroom for a new life in London

He will not show any signs of slowing down now that Labour is in government. And from his new desk in No 10 he will be closely observing exactly who visits Starmer

He will not show any signs of slowing down now that Labour is in government. And from his new desk in No 10 he will be closely observing exactly who visits Starmer

He was a restless spirit, dropping out of the London School of Economics and working for a time on building sites. After time in the U.S., he came back to London to study politics and marketing at Middlesex University in 1998.

He then joined the Labour Party in 2001 — the year of the second Blair landslide — and played a key role organising for marginal seats in 2005's election, which delivered a third successive Labour victory.

Then he hitched his colours to Steve Reed, a Labour councillor in Lambeth, South London, who was trying to wrest control of the authority from the hard-Left.

Under 'Red Ted' Knight, Lambeth was infamous, beset by mismanagement, corruption and a historical child-abuse scandal. McSweeney — who I'm told was 'solid, not spectacular' at the time — threw himself into the battle.

In Lambeth he met his future wife, Imogen Walker, who became deputy leader of the reformed council. The two share that Lanarkshire home, purchased in 2020.

In last week's election, Walker won the local (safe Labour) seat of Hamilton and Clyde Valley, by more than 9,000 votes. She is expected to be fast-tracked for ministerial promotion.

A natural in front of the cameras, she was an actress. In the 2002 Channel 4 documentary The Real Linda Lovelace, about the 1970s porn star, she played Lovelace.

After Lambeth, McSweeney went to Barking and Dagenham in East London to help vanquish the hard-Right BNP, which had won a dozen seats on the local council.

Jon Cruddas, now Dagenham MP, tells me: 'He has the psychology of an organiser, and he's quite brilliant at it. These political skills have been chiselled out over years, so he's no blow-in to anything.'

A Labour source says: 'He saw himself as a modern-day Witchfinder General. Except it wasn't witches in the ducking chair but extremists from the Left or Right.'

Within a few years, the BNP had lost every one of its council seats.

At last McSweeney turned his eyes to the national stage, running the 2015 leadership campaign of Liz Kendall, a moderate. Kendall came last with a paltry 4.5 per cent of the vote — as Corbyn romped home.

Aghast at the result, McSweeney became director of a new group, Labour Together, whose goal was to drag the party back into the centre. Early recruits included Rachel Reeves, now Chancellor, and Health Secretary Wes Streeting. They — unlike Starmer, who referred to Corbyn as his 'friend' — had both refused to join Corbyn's shadow frontbench, and were seeking an alternative leader.

As Labour Together's influence grew, McSweeney was becoming the respected backroom player he had always wanted to be. After the 2019 election, when Labour under Corbyn suffered its worst defeat since 1935, Starmer asked McSweeney to run his leadership campaign. They had at least one thing in common: they were both passionate Remainers.

After the 2019 election, when Labour under Corbyn suffered its worst defeat since 1935, Starmer asked McSweeney to run his leadership campaign

After the 2019 election, when Labour under Corbyn suffered its worst defeat since 1935, Starmer asked McSweeney to run his leadership campaign

Starmer ran on an extravagantly Corbynite ticket, pledging to scrap university tuition fees, defend free movement across Europe and hammer the rich with punitive taxes. The hard-Left policy document did the trick to satisfy the Corbynistas and Starmer won decisively in the first ballot. All ten pledges were later abandoned — on the orders of McSweeney. He has since ensured the Party's rules were altered to make it harder for Left-wingers like Corbyn to win again.

'He has been purging Lefties to ensure that after Starmer goes, a centrist takes over,' said another Labour figure who is not a fan of McSweeney. 'If he's successful he will be trying to write himself into the succession plans.'

H e's even curbed the influence of Tony Blair, whose grandly named 'Institute' provides staff and policy papers for the Labour frontbench.

A senior Labour source tells me: 'Morgan thinks Blair has had his time. While Blair can call Starmer whenever he likes, it's McSweeney whose advice he ultimately takes. Morgan thinks Blair's ideas are from a different era — that he's yesterday's man.'

Another senior figure told me: 'If it goes wrong for Starmer, he will find out how ruthless McSweeney is. Just as Boris found with [ex-adviser] Dominic Cummings.'

One Labour parliamentary candidate says: 'Starmer won the leadership on a lie because every single policy commitment he made has been junked by McSweeney. Will they do the same thing with the promises made in the election campaign? If they do, the voters will be much less forgiving.'