Britain's Shadow Chancellor of the Exchequer John McDonnell of Labour Party is seen outside the Cabinet Office, as uncertainty over Brexit continues, in London, Britain April 12, 2019. REUTERS/Peter Nicholls

LONDON (Reuters) - Lawmakers from Britain’s opposition Labour Party are unlikely to be persuaded to back Prime Minister Theresa May’s Brexit deal when she puts it to a vote in parliament next month, the party’s finance chief John McDonnell said on Tuesday.

McDonnell told reporters he would wait to see the details of May’s offer, but that what had been reported to be included so far “doesn’t inspire confidence, and I don’t think that many of our members will be inspired by it either.”

McDonnell said that regardless of what May offers on Brexit there was an overriding problem with the longer-term stability of May’s Conservative Party.

He also said he couldn’t see Labour abstaining in the vote.