Labour MPs are to rebel next week over the government’s reforms to political funding, pushing ministers to introduce tougher measures including a ban on cryptocurrency donations and much lower spending limits.

MPs on the all-party, anti-corruption group are canvassing support for four amendments to the representation of the people bill that would significantly tighten the government’s plans.

They include a permanent ban on donations made in digital currencies, instead of the government’s current moratorium, a proposal that is finding widespread support among Labour MPs after the controversies over Nigel Farage’s funding.

Liam Byrne, the Labour chair of the business select committee who is calling for a cryptocurrency donation ban,…