HSBC was warned last night that it could face further strikes in a bitter row over pay.

Union officials clashed with the company over the impact of a 24-hour walkout yesterday, with HSBC rejecting claims that a number of branches and a major processing centre had been closed.

The bank said 1,471 of its employees had gone on strike, only 2.7 per cent of its workforce, and maintained that all of its 1,500 branches, as well as processing centres and other sites, had remained open.

But the Amicus union said about 3,000 of its members had supported the industrial action and said a processing centre in Birmingham, as well as branches in Liverpool, Preston, Grantham and parts of Scotland had been closed.

National officer Rob O'Neill said the union would consider its next move but warned that more strikes could be called, hinting that the next one could be longer than one day.

Mr O'Neill joined dozens of union activists who handed out peanuts symbolising staff pay rises as shareholders arrived for the bank's annual meeting in London yesterday.