Rishi Sunak will be in Edinburgh to launch the Scottish Conservative manifesto, but the publication of the party’s pledges looks set to be overshadowed by the growing Gambling Commission probe.

Yesterday it emerged that another senior figure in the party was being investigated over bets placed on the timing of the general election.

Nick Mason, the chief data officer, has taken a leave of absence.

The latest allegations were published by the Sunday Times, which claimed dozens of bets had been placed with potential winnings worth thousands of pounds.

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Three other figures have been caught up in the scandal.

Tony Lee, the party’s director of campaigns, and his wife Laura Saunders, a candidate in Bristol, are both under investigation by the Commission.

So too is Craig Williams, who was the Prime Minister’s parliamentary private secretary and is the Conservative candidate for Montgomeryshire and Glyndwr.

He has admitted to putting “a flutter” on the date of the election three days before Mr Sunak called the vote.

Home Secretary James Cleverly was pushed on the allegations as he spoke to media on Sunday morning.

Asked on the BBC if any ministers had put a bet on the timing of the election, he said: “Not to my knowledge.”

The Home Secretary told GB News: “My view has always been the case that people in government should focus on delivering for the people of this country.

“People who are officials of the party should be focused on returning as many Conservative MPs as possible so we can form a government so that we can serve the British people.

“And anything other than that is inappropriate. So whilst I’m not going to discuss any of the details, people should focus exclusively on the people we’re here to serve.”

(Image: BBC/PA)

Yesterday, Mr Cleverly was also asked about a recording of his parliamentary aide criticising the party's Rwanda policy.

James Sunderland told a private event that the plan to send asylum seekers on a one-way trip to the African country  "is crap."

"OK? It’s crap," he added.

Mr Cleverly told Sky News’ Sunday Morning with Trevor Phillips that Mr Sunderland was “very supportive” of the policy.

The Home Secretary said: “He did it clearly for dramatic effect to grab the attention of the audience.

“But he is – and it’s clear in the recording – completely supportive of the deterrent effect that the Rwanda policy has.”

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Mr Sunak will likely face questions on both the gambling row and the internal criticism of his flagship Rwanda policy when he helps Douglas Ross launch the Scottish Tory manifesto. 

Speaking ahead of the event in the capital, Mr Ross set out five pledges as he promised his party would turn a “laser-like focus on the real priorities of the Scottish public”.

They include recruiting 1,000 more GPs and police officers, improving rural trunk roads, “backing teachers to teach and increasing subject choices for pupils” and cuts to income tax and national insurance will be at the heart of the party’s manifesto ahead of the July 4 election.

Ahead of the launch Mr Ross - who is due to stand down as leader after the election - said: “It provides solutions to the problems caused by years of SNP incompetence and poor decision-making.

“We are committed to tackling the waiting-times crisis in Scotland’s NHS by recruiting 1,000 extra GPs, the crisis in Scottish policing by recruiting 1,000 extra officers, restoring our schools by backing teachers, upgrading our neglected trunk roads and cutting taxes for hard-working Scots.

“These are the issues that matter to Scots – but which have been ignored by the SNP as they’ve focused relentlessly on independence.

“Every Scottish Conservative MP elected will be committed to delivering on these policies and the priorities of their constituents.”

Lib Dem MSP Willie Rennie said: “It's hard to tell who is having a worse campaign. From Rishi Sunak abandoning D-Day veterans to Douglas Ross facing an activist mutiny and questions over his expenses, it has been an absolutely torrid time for the Scottish Conservatives.

"Based on current form, if they launch their manifesto at a business it'll catch fire or on a farm it will get flooded."

SNP candidate for Glasgow North Alison Thewliss said it was good that Mr Sunak and Mr Ross would have time to "compare notes on which one has run the worst campaign."

"They are both on their last legs as leaders, their party is already finished in this campaign and the real choice for Scotland in this election is who is now best placed to put Scotland's interests first," she added.

Labour's Shadow Scottish Secretary Ian Murray said: "Rishi Sunak will venture to Scotland and lightweight figure Douglas Ross will come out of hiding to try and convince Scots to forget the last 14 years. 

"Voters can see the Scottish Tories' empty promises for what they are - the desperate last gasp of an irrelevant party.