Left with no option but to resign

hearing that “we [the Home Office] don’t have targets for removals”, adding: “That’s not how we operate.”

However, in the latest leaked letter to emerge over the scandal, sent to Mrs May in January 2017 and headlined “Immigration Enforcement”, Ms Rudd outlined her strategy for “arresting, detaining and forcibly removing illegal migrants”.

She also spoke of a need for “sufficient beds” to meet the “10 per cent uplift in enforced removals”. The existence of the note, written over a year before the committee hearing, was proof that Ms Rudd was aware of the targets, critics said.

It came after another leaked memo was published just a few days earlier which appeared to show Ms Rudd had been told by her officials that the department was using targets in June 2017. It was sent to Ms Rudd, her deputy Brandon Lewis and a number of other senior officials.

Answering questions about the letter on Sunday, Mr Lewis admitted that Ms Rudd had been aware of an “ambition” to increase removals by 10 per cent – but insisted that was not the same as a concrete target.

Mr Lewis, the Conservative Party chairman, told the BBC’S Andrew Marr Show: “Yes, I did talk to the Home Secretary about that [deportations] and the overall work that we were doing and the overall ambition to see an increase in numbers, but not on the detailed numbers and targets.

“What the Home Secretary was very aware of was her ambition to see an increase in the number of people who were here illegally that we were removing, particularly those foreign national offenders.” He added: “Those internal targets were not in the memo and not figures that she was aware of.

“I have been in a room with Amber Rudd talking about increasing the number of returns but Amber Rudd and I never discussed particular numbers in the way that was outlined at the home affairs select committee.”

Ms Rudd’s decision to stand down will come as a major blow to Mrs May, who publicly declared her “full confidence” in her as recently as Friday.

The former home secretary had been due to appear before the House of Commons today, during which she was expected to defend her record and vow to continue in the role.