Heavy discounting and promotions at department stores helped entince cash-strapped consumers and push up retail sales in May.

Sales volumes increased 1.4 per cent last month, following a revised 2.4 per cent drop in April, according to the Office for National Statistics.

City analysts had expected a rise of around 0.8 per cent.

The increase was driven primarily by a surge in fuel sales, as March's fuel strike threat continued to impact buying, but a fall in prices at department stores also lifted volumes.

Putting the impact of fuel sales aside, total retail sales volumes increased by 0.9 per cent.

The rate of inflation has fallen throughout 2012, from a 5.2 per cent peak last September to 2.8 per cent in May, as weak economic growth weighs on companies' pricing power.