Labour could pull its support from the Government’s Investigatory Powers Bill, if its demands for greater privacy safeguards are not met.

Shadow Home Secretary Andy Burnham has written to Theresa May to lay out Labour’s seven areas of concern about the proposed legislation, which would give more surveillance power to the police and security services.

When the bill passed its first reading last month, Labour abstained on the vote, but Burnham says that the party will oppose its further passage if the Tories do not take on board the concerns he has raised. In the letter, he writes:

“If I determine that our concerns are not satisfactorily dealt with during the passage of the bill, then we will be unable to support a timetable that puts the bill on the statute book by December this year.

“I hope that is not necessary and that we can together produce a bill that commands a high degree of confidence and trust.”

Among Labour’s demands to water down the legislation are an amendment to bill giving a presumption in favour of privacy, a higher threshold for for authorities to access the records, and further protections for sensitive professions like MPs, journalists and lawyers – which would offer greater security for communications with constituents, sources and clients. Burnham also highlights the threat to trade unionists through the “economic well-being” clause – highlighted by LabourList last week – which ministers claim will protect vital commercial infrastructure.

Burnham said in the letter to May: “I hope you will accept that the seven points I have outlined are legitimate concerns and that you will work with us to address them properly.”