Vince Cable: Spending cuts 'necessity not choice'
Union delegates have backed joint industrial action if "attacks" on jobs, pensions and public services go ahead.
The TUC's annual gathering backed a motion which included calls to build "a broad solidarity alliance of unions and communities under threat".
TUC chief Brendan Barber warned that big cuts would make Britain a "dark, brutish and more frightening place".
Business Secretary Vince Cable denied the cuts were an attack on the public sector.