His premiership has been dominated by problems with small boats, but Rishi Sunak must have thought he was safe on the River Thames today. 

But even in Middle England he could not escape irritation at the hands of tiny watercraft.

The Prime Minister and his team chose England's longest waterway as the backdrop for a campaign visit to Henley, where the migrant crisis in the Channel was not on the agenda.

But none-the-less, the visit to a rowing club was marred by unwelcome visitors on the water - in the form of a photobombing boatload of Liberal Democrats. 

The PM was spotted by Lib Dem deputy leader Daisy Cooper while she also campaigned in Oxfordshire, as part of the party's attack on Tory Blue Wall seats. 

And she was quick to rustle up a boarding party of placard waving activists who motored past behind the oblivious Mr Sunak in full view of the television cameras following him on the trail. 

A Lib Dem source said: 'This is just another small boat Rishi Sunak can't deal with.' 

The Prime Minister and his team chose England's longest waterway as the backdrop for a campaign visit to Henley, where the migrant crisis in the Channel was not on the agenda.

The Prime Minister and his team chose England's longest waterway as the backdrop for a campaign visit to Henley, where the migrant crisis in the Channel was not on the agenda.

The PM was spotted by Lib Dem deputy leader Daisy Cooper while she also campaigned in Oxfordshire, as part of the party's attack on Tory Blue Wall seats.

The PM was spotted by Lib Dem deputy leader Daisy Cooper while she also campaigned in Oxfordshire, as part of the party's attack on Tory Blue Wall seats.

And she was quick to rustle up a boarding party of placard waving activists who motored past behind the oblivious Mr Sunak in full view of the television cameras following him on the trail.

And she was quick to rustle up a boarding party of placard waving activists who motored past behind the oblivious Mr Sunak in full view of the television cameras following him on the trail.

Henley has voted Tory since 1910, but Sir Ed Davey's party believes it is a realistic target. It is becoming Henley and Thames, with changed boundaries, at the coming election under a recent boundary review.

As the Prime Minister visited a riverside rowing club and spoke with female members, Ms Cooper and her crew rode past on a boat.

The Lib Dem contingent, who were also campaigning in the same area, carried orange diamond shaped voting placards during the incident, waving them towards the Prime Minister and the media following him during the visit.

Mr Sunak was joined on the visit by two Conservative candidates for nearby constituencies: Caroline Newton for Henley, and Lucy Demery for Wokingham.

The Prime Minister cleaned down the hull of a rowing craft alongside club members, and stopped for a cup of tea on the riverside where he spoke with other members about their time at the club.