Tom Tugendhat has launched his bid for the Tory leadership with a promise of a “Conservative revolution” and a return to integrity in politics.

In a speech on Tuesday, the former security minister said he would use his party’s period in opposition to prepare for action “on day one” of a new government, saying his mission is “the happiness and prosperity of the British people”.

He said: “The last great economic transformation that our country saw was in the 1980s – some of you will remember it well.

“Since those changes, Britain’s creeping bureaucracy has returned and it’s stifling growth and it’s smothering opportunity.

“And we need to clear back those cobwebs so that once again our economy – and most importantly, of course, our people – can breathe free and make our country grow again.”

Promising to “listen to the serious ideas that come to us”, he swore to deliver on economic growth by “releasing the brake” and ensuring the country has the right skills and the right infrastructure.

The entire purpose of international treaties is to keep British people safe, not for us to worship international treaties

Mr Tugendhat leant heavily on his experience as a soldier and as security minister, devoting a section of his speech to foreign affairs and saying he would set out a plan to spend 3% of GDP on defence.

He said: “The purpose of British foreign policy is to keep the British people safe and prosperous.”

But he also used that experience as an explanation for why he had not spoken out against things he disagreed with while serving under Liz Truss and Rishi Sunak.

He said his job had been “to keep the King’s secrets”, adding: “Those who are trying to kill us kept me busy enough already.”

Mr Tugendhat had begun his speech with an apology and a promise to be “sober and serious”, saying the Conservative Party “owes you better” and has seen “duty give way to ego”.

With immigration becoming a major theme of the Tory leadership election, he promised to reduce migration and reiterated his willingness to leave the European Convention on Human Rights (ECHR) if it prevented the government from deporting foreign criminals and he was unable to reform it.

He cited cases in Australia where naturalised citizens had been stripped of their citizenship after committing serious crimes, and in Germany where offenders had been deported to Afghanistan.

Mr Tugendhat said: “The entire purpose of international treaties is to keep British people safe, not for us to worship international treaties.”

One of Mr Tugendhat’s rivals, former immigration minister Robert Jenrick, has also said he would leave the ECHR, but faced veiled criticism from other contenders for his stance.

Kemi Badenoch and James Cleverly both spoke unfavourably of the plans, suggesting Mr Jenrick was offering “easy answers” or “soundbites and quick fixes” which would not deliver results.

Mr Jenrick hit back, telling reporters: “On illegal migration… if you come here illegally, you’re detained, you’re removed within days either back to Albania or to a safe third country like Rwanda, whatever is available in the years ahead.

“To do that, I have come to the conclusion that we have to leave the European Convention on Human Rights. I don’t believe it’s reformable.”

Mr Tugendhat’s speech on Tuesday, the final launch event of the Conservative leadership contest, came just one day before the first round of voting by Tory MPs.

MPs will narrow the field of six candidates down to four ahead of the Conservative Party Conference at the end of September, after which MPs will further whittle down the hopefuls to just two.

Those two will then be voted on by Tory members, with the winner expected to be declared on November 2.

Mr Jenrick currently leads the pack, with 17 MPs declaring their support for him, while former business secretary Ms Badenoch follows him with 13 declared supporters.

Mr Tugendhat has seven declared backers among MPs, the same number as former work and pensions secretary Mel Stride and one more than former home secretary Mr Cleverly.

Former home secretary Dame Priti Patel brings up the rear with just five MPs publicly saying they will support her campaign.

All six candidates are expected to take part in a hustings on Tuesday afternoon prior to the vote on Wednesday.