Sir Graham Brady suggested his colleagues should not try to oust Theresa May because doing so could undermine Brexit negotiations as he revealed some Tory MPs had lied about submitting no confidence letters.

The chairman of the 1922 Committee of backbench Conservative MPs confirmed on Sunday the threshold for a ballot on the Prime Minister’s leadership had not yet been crossed.

He said he personally believed a ballot would not be “helpful” as he refused to be drawn on how close to the magic number of 48 letters he was and insisted he was the only person who knew, with even his wife being kept in the dark.

Meanwhile, Mrs May said she was in regular contact with Sir Graham as she urged Tory MPs not to submit letters and warned a no confidence vote and a potential leadership contest risked stopping Brexit.

Close to 30 Tory MPs have publicly claimed to have submitted a letter to Sir Graham.

But the influential backbencher said any and all claims of letter writing should be viewed with a degree of suspicion because some MPs had claimed to have submitted one when they actually had not.

As the sole keeper of the letters, Sir Graham is at the centre of a fierce tug of war between disgruntled Eurosceptic Tories and Mrs May who is still in the process of trying to shore up her Government after it was rocked by a handful of ministerial resignations over her Brexit deal.