It’s the endorsement both candidates desperately wanted in the battle for the Tory crown.

And potentially the biggest vote winner, declaring for Liz Truss so far.

Penny Mordaunt was runner-up to Rishi Sunak in all but the final round of voting by MPs, before being narrowly edged out by Liz Truss in the nail-biting 11th-hour showdown.

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In round one she won 67 votes to 50 for Ms Truss, in round two it was 83-64, round three was 82-71 and round four 92-86, before she finally polled just 105 to 113 for Ms Truss.

Now, in a shock move after the bad blood between their two camps during the MPs’ voting, the former magician’s assistant has sprinkled her stardust on the Liz Truss campaign.

In a stunning piece of theatre at the Tory party’s hustings at the University of Exeter, she dramatically climbed on board the Truss bandwagon and almost certainly earned herself a cabinet job if the foreign secretary defeats Mr Sunak.

Cynics will claim Ms Mordaunt’s endorsement of Ms Truss would have carried more weight had it come earlier.

But the timing – the day ballot papers were being sent to party members – is ideal for Ms Truss and a crushing blow to Mr Sunak.

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Inside the hall, the moment when Ms Mordaunt was introduced as Ms Truss’s cheerleader and warm-up act was pure box office.

The backers of the two leadership candidates had been kept under wraps until the hustings got underway.

Her backing for Ms Truss is a remarkable U-turn.

When her campaign to reach the top two had real momentum last month, there were claims that she was the victim of smears and dirty tricks by the Truss campaign.

Cabinet Secretary Simon Case was forced to bow to demands from Ms Mordaunt’s supporters for an inquiry after accusations that civil servants leaked information to the press to damage her chances in the race.

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As the early bookies’ favourite and the darling of party activists according to several polls, she had been attacked over her stance on trans issues and claimed her views had been misrepresented.

Later there were claims that she was lazy and “went missing” in her job as an International Trade minister, neglecting her duties because she was plotting a leadership campaign.

Aged 49, two years older than Liz Truss, Ms Mordaunt is a Royal Navy reservist and took part in a TV reality show called Splash wearing a swimsuit. Now she’s made her biggest splash yet in the Tory leadership campaign.

Rishi Sunak and Liz Truss will take part in a head-to-head debate on Sky News on Thursday 4 August at 8pm hosted by Kay Burley.

If you would like to be a member of the live studio audience and be in with a chance of asking a question, please apply here.