Profit warnings from industrial heavyweights Rolls-Royce and Tate & Lyle sent their shares sharply lower during a poor session for the FTSE-100 Index.

Rolls shares dived 14% and Tate was 16% lower, while Lloyds Banking Group was also under pressure in the wake of full-year results, despite confirming its return to bottom line profit for the first time in three years.

The FTSE-100 Index fell by as much as 65 points at one stage as a raft of blue chip banks joined Lloyds in the red, although the top flight later recovered some lost ground to finish 15.6 points lower at 6659.4.

The pound strengthened against the US dollar, standing at 1.66 , but the sterling was slightly lower against the single currency at 1.21.

Rolls and Tate were by far the biggest fallers of the session after their profit alerts.

Shares in engines giant Rolls dived 165p to 1045p after it warned that profits and revenues will fail to grow this year as a result of defence spending cuts.

There was a similar reaction to guidance from sweeteners and food ingredients business Tate that tough trading conditions in established markets meant profits would be flat in the current year.

Shares slumped 126.5p to 660p as it also highlighted the prospect of weaker sucralose prices.

Shares in Lloyds Banking Group lost some of their recent froth after the bank announced a return to the black in 2013 with bottom line profits of £415 million.

Sentiment towards the bank has been impacted by the continued rising bill for payment protection insurance mis-selling and the City's wait for a restoration in dividend payments, with the stock down 2.2p to 81.3p.

Engineering and project management company Amec also finished lower after it unveiled a definitive agreement to buy rival Foster Wheeler. Its shares initially jumped on the news but later finished 12p lower at 1080p.

British Airways and Iberia owner International Airlines Group rose 12.4p to 442p after unveiling an agreement between the Spanish airline and its pilots' union, SEPLA, over productivity changes. IAG said that Iberia would become more competitive and cost effective as a result of the deal.

Imperial Tobacco finished as the top riser in the FTSE-100 Index after it said net revenues rose 1% in the quarter to December 31, despite a 5% fall in volumes. Shares were 126p higher at 2351p.

The biggest FTSE-100 risers were Imperial Tobacco up 126p at 2351p, International Airlines Group ahead 12.4p at 442p, British American Tobacco up 57p at 3052p and Randgold Resources ahead 69p at 4687p.

The biggest fallers were Tate & Lyle down 126.5p at 660p, Rolls-Royce off 165p at 1045p, Aberdeen Asset Management down 19.4p at 408.2p and Tullow Oil off 34p at 758.5p.