Pilkington rejected two previous takeover offers

The Japanese firm has offered to buy the 80% of Pilkington it does not already own for �1.8bn ($3.14bn).

The move brings to an end to three months of talks between Pilkington, whose head office is in St Helens, Merseyside, and Nippon Sheet.

The 180-year-old UK glassmaker employs almost 24,000 people and also has factories in Birmingham and Doncaster.

Under the cash deal, Nippon Sheet will offer 165 pence a share - up from its previous offer of 158p.

Pilkington had rejected two previous offers from the Japanese firm, saying the price was too low.

As the deal was announced, Nippon Sheet also said it would raise a total of 110bn yen (�543m, $946m) through the issue of a convertible bond.

Competitive edge

According to analysts, the deal will lead to savings at Nippon Sheet as the firm will be able to combine its UK subsidiary NGF Europe with Pilkington's head office, both of which are located in St Helens.

The tie-up will also mean serious competition for the world's current leading glass maker Asahi of Japan which has a quarter of the global market. Pilkington is a close second with about 19%, while Nippon has about half that.

In November, Pilkington unveiled a 22% jump in first-half profits to �99m despite surging energy costs.

Pilkington chief executive Stuart Chambers said: "Over the past nine years Pilkington has significantly improved its cost structure to become leaner and more profitable.