Labour’s shadow chancellor has slated the Liberal Democrats as the “extreme right-wing austerity party in this country”.
John McDonnell told talkRADIO: “[Jo] Swinson was talking about tough choices to be made about spending and investment and public services.
“They’re not tough choices for her, they’re tough choices for the queues of families in the food banks, the disabled people not getting their benefits.”
His comments came ahead of a key note speech in which he pledged that a Labour government would reduce the UK’s average working week to 32 hours within 10 years.
During his address at his party's conference in Brighton, Mr McDonnell promised a shorter working week with “no loss of pay”, saying "we should work to live, not live to work”.
“People in our country work some of the longest hours in Europe.
"So I can tell you today that the next Labour government will reduce the average full-time working week to 32 hours within the next decade.”
He also committed to eliminating in-work poverty within the first term.
On Brexit, the MP for Hayes and Harlington told talkRADIO that the Lib Dems were “a threat to the country”.
“They’ve gone to quite an extreme in terms of revoke without any referendum - I think that’s unacceptable.”
Speaking later to his party, Mr McDonnell said Labour was right to "trust the people in having the final say on Brexit - a deal or remain".
He said: "Some of you will know I have said that I will campaign for remain but let me be absolutely clear - I profoundly, I profoundly, respect those who support a genuine alternative.
"I warn those who would revoke Article 50 without a democratic mandate, just ask yourselves what message that sends to our people?"