Top secret letters that will be destroyed when Boris Johnson leaves office

So no pressure then.

When she enters No.10 Downing Street tomorrow, she will be given a security briefing by the cabinet secretary, national security adviser and chief of the defence staff.

They will very calmly explain to her what her options are if faced with nuclear Armageddon and the death of millions of Brits at some point during her tenure.

Truss will then be left alone to think over her decision, writing it down in what are known as the Letters of Last Resort.

These are sent to the commanding officers of the four British ballistic missile submarines - Vanguard, Victorious, Vigilant and Vengeance - the locations of which are top secret.

In those letters Truss will set out one of four options; to retaliate, to do nothing, to place the submarine under the control of an ally - namely the US or Australian Navy, or whether to leave the decision to the captain.

These will be placed in envelopes, sealed, and sent out to the four commanders, where they will remain unopened and locked away until the pretty harrowing time comes.

Boris Johnson's letters, which he too will have had to write when he came to office in 2019, will remain sealed and then burned.

The PM's decision is usually kept a secret, however, Truss was recently asked about her view on nuclear war during her leadership contest with Rishi Sunak.

And it would seem that she would have no problem with unleashing the UK's arsenal if the question was put to her.

Speaking to Times Radio, she said: "I think it's an important duty of the prime minister and I'm ready to do that.

"I'm ready to do that."

Truss was named the new prime minister at a press conference this afternoon (5 September).

The chairman of the 1922 Committee Sir Graham Brady announced the winner at a press conference this afternoon.

Speaking following the result, Truss, who is the third female prime minister in the country's history, said she was proud of the contest and thanked the 'outgoing leader and my friend, Boris Johnson'.

She praised him for 'crushing Jeremy Corbyn' and 'standing up to Vladimir Putin', saying he was 'admired from Kyiv to Carlisle'.

Truss said: "We all will deliver for our country and I will make sure that we use all the fantastic talents of the Conservative Party, our brilliant Members of Parliament and peers, our fantastic councillors, our MSs, our MSPs, all of our councillors and activists and members right across our country.

"Because my friends, I know that we will deliver, we will deliver and we will deliver.

"And we will deliver a great victory for the Conservative Party in 2024."