David Cameron will slap more shackles on trade unions “on day one” of a future Conservative government in a bid to snuff out workers’ right to strike, London Mayor Boris Johnson revealed yesterday.

Members of Tube union RMT woke up to the news on day two of a crippling 48-hour strike over London Underground cuts.

Wealthy Tory Mr Johnson bragged on local radio that the Prime Minister had confirmed “from his lips in public” that one of his first steps if re-elected in 2015 would be draconian new laws that include a clampdown on industrial action in London.