Rishi Sunak today hailed Boris Johnson's Tory election campaign support, saying it 'will make a difference' to party fortunes on July 4.
The Prime Minister praised his predecessor for giving personal endorsements to a number of Conservatives seeking re-election.
Mr Johnson, who is currently in Sardinia with his family, has recorded video messages for Tories including Sir Simon Clarke, Paul Bristow, Nick Fletcher, Tom Hunt and Jane Stevenson.
It came as Mr Sunak underlined the Tories defensive strategy today as he campaigned in North Devon.
The PM joined former Attorney General Geoffrey Cox in Torridge & Tavistock - where he had a notional majority of nearly 23,000 at the 2019 election.
The pair joined a group of fishermen catching lobster, as well as chatting to local activists on the beach in Clovelly.
He later went on to visit North Devon, where Selaine Saxby is defending a majority of almost 15,000.
But Mr Sunak's focus on previously ultra-safe seats will heighten alarm within the party about the prospects of a near-wipeout on July 4.
The Prime Minister praised his predecessor for giving personal endorsements to a number of Conservatives seeking re-election.
Mr Johnson has recorded video messages for Tories including Sir Simon Clarke, Paul Bristow, Nick Fletcher, Tom Hunt and Jane Stevenson.
A huge Survation poll - conducted using so-called MRP technique - showed Sir Geoffrey losing his seat, with the Conservatives reduced to just 72 MPs.
Speaking to broadcasters today Mr Sunak said: 'It's great that Boris is supporting the Conservative Party, I very much welcome that.
'He is endorsing many candidates in videos and letters which have been coordinated by the campaign. I know that will make a difference.
'And of course every week he is making the case in his column and making sure that everyone understands what the Labour government would do to this country and why it's important that everyone votes Conservative. And I am glad he is doing that.'
He also denied claims that other high-profile Tory figures have been kept away from the campaign trail, insisting 'they've all been campaigning lots'.
The Prime Minister was joined by Foreign Secretary Lord Cameron in north Devon on Tuesday, but has been accused of running a presidential-style General Election campaign with little involvement from other Cabinet ministers.
Asked about the claims, he told reporters on the visit: 'I don't think that's quite fair.
'They've all been campaigning lots, right? Like David's (Cameron) been out and about a lot campaigning in lots of places... Claire (Coutinho) was with me yesterday. Penny's (Mordaunt) been doing the multi-party debate, right?
'So you're seeing the full team out there doing lots of campaigning.'
He also joked that 'as far as I can tell, I can't turn on the TV screen without seeing Grant (Shapps)'.
The MRP poll suggested that Keir Starmer could win by an incredible margin of 262, with Nigel Farage 's Reform picking up seven MPs.
Home Secretary James Cleverly was projected to lose his Braintree seat, while Chancellor Jeremy Hunt would fall victim to the Lib Dems in Godalming and Ash.
Election experts have been warning that previously ultra-safe seats are under threat as the party's core vote is collapsing - comparing it to Churchill's defeat at the 1945 election.
Tories are urging Mr Sunak to take the gloves off against Nigel Farage as the battle to stave off the Reform threat intensifies.
Anxiety has been mounting about the passive approach being taken by the PM, as the insurgents gain ground in the polls.
Senior Conservatives warned that the current strategy of largely ignoring the Brexit champion and focusing fire on Labour is 'not working', insisting that Mr Sunak needs to get 'personal' to stop the party bleeding votes.
One Cabinet minister told MailOnline that the tactic of not uttering Mr Farage's name - similar to the treatment of Lord Voldemort in Harry Potter - is 'ludicrous' and Mr Sunak looks 'scared'.
Another ex-minister voiced alarm that their majority of around 20,000 was 'touch and go', and the premier had to recognise that Reform was the 'real enemy' rather than Labour. They said of Mr Farage: 'Rishi can't beat him on personality. But Rishi can try to laugh off his absurd policies... our attack has to be direct.'
The defending MP added: 'It is insane to ignore him the way they are at the moment... they need to get personal.'
The internal Tory wrangling came after another poll showed Reform level with the Tories, and Mr Farage unveiled a huge tax cutting and spending manifesto.
Reform were up a point with Redfield & Wilton Strategies, alongside the Tories on 18 per cent - both a full 25 points behind Labour.