The Tory party chairman has insisted the online membership vote to choose a new leader and the next prime minister will be “secure”, just months after the process was revamped over hacking concerns.

Speaking outside Parliament, Sir Jake Berry declined to give details on the safeguards in place but said he was “satisfied” there would not be any cyber security issues in the contest to replace Liz Truss.

Questioned on safety concerns over the binding online vote, Sir Jake said: “Without going into the security measures we will take… we are satisfied that the online voting system will be secure.”

He added that “all efforts would be made” to reach members who did not have access to the internet.

In the previous Tory leadership race, party members were initially told they could vote by post and amend their decision online until the system was reformed in early August.

The National Cyber Security Centre, which is part of GCHQ, warned that the process was vulnerable to interference, forcing the party to delay sending out ballot slips.

Those opting to cast their vote online had to submit a single-use code and answer security questions.

Sir Jake confirmed that a membership vote would not take place if only one candidate had reached the nomination threshold of 100 MPs by Monday.