Boris Johnson is seeking to focus attention on tackling crime and the coronavirus recovery amid signs a string of allegations may be damaging the Tories’ ahead of the elections.

The Prime Minister said on Sunday he had “no doubt” the economy “will bounce back strongly” from the pandemic in a pitch to voters before polls open across Britain on Thursday.

He made the pitch as two new surveys suggested the Conservatives’ lead over Labour has been cut ahead of local elections in England and votes for the parliaments in Scotland and Wales.

The polls will raise concerns among Conservatives that recent “sleaze” allegations battering the Prime Minister are beginning to turn some voters off.

The Electoral Commission this week launched an investigation into whether any donations or loans to pay for the lavish refurbishment of his Downing Street flat were properly declared.

And Mr Johnson has been forced to deny saying he would rather see “bodies pile high” than impose a third coronavirus lockdown, on top of a lobbying row and allegations of cronyism.

The Prime Minister appealed to voters in an article for The Mail on Sunday by saying he would “bring the hammer down hard on the gangs” and set up a “pet theft task force”.

He said the roll-out of vaccines, one popular element of his handling of the pandemic, was helping to ease restrictions ahead of the expected relaxations on May 17 and June 21.

“This country is moving forwards cautiously but I hope irreversibly through the steps of the roadmap,” Mr Johnson wrote.

“Week after week we are seeing how the vaccine rollout is helping to restore our freedoms – and with those freedoms I have absolutely no doubt that our economy will bounce back strongly.”

However, a fresh controversy emerged with The Sunday Times reporting an MP has received a complaint from a Tory donor that they were asked to pay for a nanny for Mr Johnson’s one-year-old son Wilfred.

The donor was alleged to have said: “I don’t mind paying for leaflets but I resent being asked to pay to literally wipe the Prime Minister’s baby’s bottom.”

A No 10 spokeswoman said: “The Prime Minister has covered the cost of all childcare.”

But she did not respond when asked if Mr Johnson paid for the original bill himself or had reimbursed somebody else.

Although earlier polls suggested the “sleaze” allegations were not significantly denting public support for the Tories, fresh surveys gave evidence to the contrary.

The Conservatives fell to a five-point lead over Labour, with 42% compared to 37%, according to the Opinium poll of more than 2,000 adults between Wednesday and Friday.

That put the Tories down two points and Labour up four compared to a week earlier, halving the Conservatives’ lead ahead of the elections, in which some 48 million people are eligible to vote.

And in separate polling, Focaldata put Labour on 39%, one point behind the Tories, who previously had a healthy lead, according to The Sunday Times.

Mr Johnson has denied breaking any laws over the refurbishment of his official residence in No 11 and insisted he had paid “personally” for the works.

But he has refused to say whether he received an initial loan from the Tory party, as Downing Street launched two separate reviews into the controversy.

Questions intensified when former aide Dominic Cummings accused Mr Johnson of wanting donors to “secretly pay” for the works in a “possibly illegal” move.

The elections on Thursday will be the first major electoral test for the Conservatives and Sir Keir Starmer’s Labour Party since the 2019 general election.