Labour is calling for an urgent investigation after a Cabinet minister deemed it was “legitimate” for former attorney general Sir Geoffrey Cox to earn hundreds of thousands of pounds advising the British Virgin Islands in a corruption probe launched by the Foreign Office.

Dominic Raab, who as foreign secretary launched the commission of inquiry into what he called “very serious” allegations in the governance of the islands, said it was useful for Parliament to have some knowledge of what was going on in the overseas territory.

But Mr Raab, who is now Justice Secretary and Deputy Prime Minister, said it is for voters to decide whether they feel Sir Geoffrey is dedicating enough time to being an MP.

The most recent register of financial interests showed that Torridge and West Devon Conservative MP Sir Geoffrey will earn more than £800,000 from Withers, an international law firm appointed by the British Virgin Islands (BVI) government in January.

But Labour’s chair Anneliese Dodds, in a letter to the Prime Minister, said: “The people of Torridge and West Devon must be wondering if Geoffrey Cox is a Caribbean-based barrister or a Conservative MP.”

No 10 said Boris Johnson felt an MP’s duties in Parliament must come first, but would not be drawn on individual cases.

A spokesman for the Prime Minister said Mr Johnson thought an “MP’s primary job is and must be to serve their constituents and to represent their interests in Parliament”.

He said: “They should be visible in their constituencies and available to help constituents with their constituency matters.

“If they’re not doing that, they’re not doing their job and will rightly be judged on that by their constituents.”

In the latest update to the register of financial interests published by Parliament, Sir Geoffrey disclosed that from September 28 this year until further notice, he will be paid £400,000 a year by Withers for up to 41 hours of work per month.

The documents show Sir Geoffrey also received from Withers this year:

– £52,535.84 for 60 hours of work between January 25 and February 28

– £45,354.48 for 55 hours of work between February 28 and March 26

– £72,569.39 for 89 hours of work between March 26 and April 29

– £156,916.08 for 140 hours of work between April 29 and May 31

– £63,143.03 for 50 hours of work between June 1 and June 30

– £46,716.29 for 40 hours of work between July 1 and July 31

He also registered a total of £133,603.84 for other legal work.

Ms Dodds said, in her letter to Mr Johnson: “It appears that your former attorney general is profiting from advising an administration accused of corruption and tax avoidance.”

She added: “It seems Sir Geoffrey took advantage of Covid-related parliamentary rules and flew out to the BVI to vote by proxy from the other side of the Atlantic.

“The irony is not lost on me that he arrived in the Caribbean on the day that those MPs who actually feel a sense of duty to their constituents were debating global anti-corruption standards.”

But earlier, Mr Raab told BBC Radio 4’s Today programme that it was not for him to “get comfortable with” the situation.

And he added that such an arrangement is a “legitimate thing to do as long as it is properly declared”.

He told Times Radio: “In relation to the British Virgin Islands, I was the foreign secretary that commissioned a commission of inquiry, given the allegations of misgovernance and very serious ones, including criminal wrongdoing.

“Now, I’m not going to get dragged into what individual MPs do, but actually having the former attorney general – and it wasn’t my decision, he was hired by the government of the BVI to advise them on how to correct and deal (with) and address those allegations – actually, is a legitimate thing to do as long as it’s properly declared.

“And, of course, it’s quite important in that Parliament, which is responsible residually for some areas of our relationship with the overseas territories, we’ve got some knowledge of what’s going on in those territories.”

Among the allegations being examined in the investigation are that public servants, community leaders and people in the media had been intimidated to such a degree that they spoke of living in a “climate of fear”.

It was claimed that funds set aside for struggling families during the pandemic had been “reallocated to political allies”, while government contracts had been awarded without any proper procurement process.

The PA news agency has contacted Sir Geoffrey’s office for comment.

The row is the latest in days of allegations over Tory sleaze, which started last Wednesday when MPs were ordered to vote for a new committee to consider an altered system of appeals after former environment secretary Owen Paterson was sanctioned, only for ministers to backtrack hours later after opposition parties refused to co-operate.

A spokesman for the Prime Minister said on Tuesday: “We recognise the strong views on this particular point and having listened to those again yesterday afternoon, we will table a motion tonight for next week to formalise the change of approach by unpicking the amendment.”

The disclosure about Sir Geoffrey comes as another Tory MP is under investigation by the Parliamentary Commissioner for Standards, Kathryn Stone, who carried out the inquiry into Mr Paterson.

Daniel Kawczynski, the MP for Shrewsbury and Atcham, is listed on the parliamentary website as being under investigation for “actions causing significant damage to the reputation of the House as a whole, or of its members generally”.

The Daily Mail reported that the inquiry relates to a suggestion that he made an “insincere” apology in the Commons after an earlier standards investigation found he had bullied parliamentary staff.

Mr Kawczynski’s office declined to comment on the newspaper’s report.