The five biggest banks in Britain will enforce the limits on bonuses agreed by world leaders at the G20 summit in Pittsburgh last week, UK chancellor Alistair Darling said today.Barclays, HSBC, Lloyds, RBS and Standard Chartered have all signed up and will hope overseas rivals follow suit.Darling said after the G20 gathering 'the party has got to be over' for bankers. G20 leaders said a large part of bonuses should be deferred and be subject to clawback.They also want financial institutions to restrict the size of the bonus pool in relation to their total income.In a joint statement, the five banks said 'it is essential that banking reward is consistent with effective risk management and that there is parity both nationally and internationally on these issues'.