By Alexandra Rogers, political reporter
The UK's largest trade union saw its membership jump by 200% in the 10 local authorities won by Reform at last month's local elections.
Unison figures show its membership increased by an average of 272% in the week after the results were announced, which saw Reform take control of 10 councils and pick up more than 600 councillors.
The data, shared with Sky News, shows an average of 64 people joined the union in the week beginning 5 May, following the poll in England on 1 May - compared with an average of 28 for the previous week and 21 for 2025 as a whole.
In a speech celebrating his party's gains, Mr Farage warned workers at councils now controlled by Reform - including Durham, Kent, Doncaster and Staffordshire - to seek "alternative careers" if they worked on diversity or climate change initiatives.
Mr Farage has sought to bring the Trump administration's so-called Department of Government Efficiency - nicknamed DOGE - to the UK in a bid to slash the costs of the state.
He has singled out council spending and environmental policies for particular criticism.