South Dorset MP Richard Drax says he is backing former prime minister Boris Johnson in the Tory leadership race.

Mr Drax suggested Mr Johnson - whose premiership was marked with a series of scandals and who was forced out of office in the summer - had 'done his time in the sin bin' and now it was time for him to return.'

Mr Johnson returned to the UK today to plot a bid to return as prime minister in a move that has divided opinion among Conservative MPs, including his former allies.

He arrived at Gatwick Airport on Saturday morning with his family after breaking off a holiday in the Dominican Republic following Liz Truss's forced resignation on Thursday.

Mr Johnson's ally Sir James Duddridge claimed he has the backing of the 100 MPs required to be on Monday's ballot, but many of them have not publicly declared that support.

He is likely to be opposed in the leadership race by his former chancellor Rishi Sunak, whose resignation was key in Mr Johnson's departure from Downing Street this summer, as well as Commons Leader Penny Mordaunt.

And, while he is yet to formally declare he will run, Mr Johnson's potential reinstatement has divided opinion even among his allies in the parliamentary party, including his former deputy prime minister and foreign secretary Dominic Raab.

Appearing on the broadcast round on Saturday morning, Mr Raab said "we cannot go backwards" and pointed out Mr Johnson faces a probe into his actions over partygate.

But Mr Drax, who says he is among the 100 MPs backing Mr Johnson, said: "I am supporting Boris Johnson as he is the only one of the candidates that has the mandate to lead the party and country. He’s done his time in the sin bin and it’s time for him to return, select the best team we have around him, and get on with governing the country.

"We need grown-up government and those chosen to lead must step up to the plate, forget their differences, unite and take the country forward through some very challenging times.”

Asked whether Mr Johnson was a credible candidate given the series of scandals he was involved in, Mr Drax said: "We must get behind whoever wins ... it’s as simple as that."

Meanwhile, writing in his online diary, Mr Drax said of Liz Truss: "You'd have to have a heart of stone not to feel sorry for Liz Truss as, once again, our prime minister stepped out of No 10 and resigned after only weeks in office.

"Personally, I feel she has been treated appallingly by some in my party. Like Boris before her, she was stabbed in the back and the front to the point she simply could not continue."

West Dorset MP Chris Loder has yet to declare who he will be supporting.

Tory MPs will vote on Monday, and two candidates will be put forward to the Tory membership unless one pulls out, with a result being announced on Friday.

Candidates have until 2pm on Monday to secure the 100 nominations, limiting the ballot to a maximum of three candidates.

Supporters of Mr Johnson believe that if he can make it to the last two, he will win in the final online ballot of party activists with whom he remains hugely popular.

Some MPs have warned they would resign the Tory whip and sit in the Commons as independents if Mr Johnson returns to Downing Street.