Fears over the UK's reliance on imported energy have been fuelled after a report claimed Britain was just six hours away from running out of stored gas in March.

High demand during another freezing month combined with a pipeline fault to drive stores of gas "dangerously low", the Crown Estate said.

Blue-chip shares slipped back again as the FTSE 100 Index continued its retreat from near-record highs after a previous session that saw the London market's biggest fall in a year.

Traders continued to take profits after a 14% rise in the index in the year to date as the top flight slipped another 42.4 points to 6654.3.

Investors recovered their poise after a shaky start to trading on Wall Street that sent stocks sharply lower.

US markets plummeted immediately after the opening bell following a global slump prompted in part by an unexpectedly weak report on manufacturing in China. Concern that the Federal Reserve might ease back on its economic stimulus programme sooner than expected had also riled investors.

India's Tata Steel has plunged into the red with losses of £840 million after wiping £1 billion off the value of its European arm, which employs 18,500 people in the UK.

The overall post-tax figure for the group represents a sharp fall from the previous year's £642 million profit, and is largely accounted for by the write-down.

Checkout staff at Tesco have seen their annual shares bonus pot halved after the supermarket giant slumped to its first annual profits fall in nearly 20 years.

The retailer said 280,000 UK staff will share a payout worth £56 million, down from £110 million a year earlier and worth a maximum of £1,625 per worker.

A shares plunge wiped £36.6 billion off the value of the FTSE 100 as a global stock market slump saw it suffer its biggest one-day reverse in a year.

The sharp 2.1% fall marked the end of a "giddy" spiral that had threatened to take the index to record highs despite the wider economy remaining relatively subdued.

Halfords has warned of a long uphill slog to recovery as profits tumbled by 22% and its dividend was slashed by a third to pay for a £100 million revamp of the struggling car parts and cycling retailer.

New chief executive Matt Davies pledged to refresh tired-looking stores and improve customer service over the next three years but warned that earnings were unlikely to recover until 2016.

Mitchells & Butlers, the UK's biggest operator of managed pubs with 1,600 sites, has placed upmarket, special occasions and family dining at the centre of an investment drive worth up to £80 million a year.

The Harvester, O'Neill's and All Bar One owner, which employs 40,000 people, said the three sectors were worth £35 billion and currently benefit from the most attractive consumer trends.

The UK's return to growth has been underlined as revised figures confirmed the dominant services sector helped the economy expand by 0.3% in the first three months of the year.

Services shook off the freezing start to the year, with a recovery from hotels and restaurants helping the sector grow by 0.6% in the first quarter, the Office for National Statistics (ONS) said.

Shares have taken a dive on the FTSE 100 Index as a surge which threatened to take it to an all-time high was cut short following poor economic figures from China.

Comments from Federal Reserve chairman Ben Bernanke that US policymakers could slow the pace of their support in the next few months also spooked markets, with the FTSE 100 Index down by 2.1% or 143.5 points to 6696.8.