But Opec hawks Iran, Libya, and Algeria warned in a statement that market stability is a responsibility of non-Opec as well as Opec producers, implying they might oppose the production increases.

BBC: Opec to boost oil output

Conservative MP Peter Bone said the "first duty" of the deputy PM was to "support the prime minister", and claimed Mr Clegg had "swished away" the doctrine of collective responsibility by making a separate statement.

BBC: PM 'wary' of Leveson recommendations on press law

Separately, conservative Democrats in the House, who have been pushing for a strong statement from leadership on fiscal responsibility in the budget, may have some of their concerns addressed.

CNN: Budget resolution 'a major accomplishment,' negotiators say