Kidde PLC, a British fire and safety equipment maker, said that United Technologies Corp. boosted its takeover offer for Kidde, which agreed to open its books to the <?xml:namespace prefix = st1 ns = “urn:schemas-microsoft-com:office:smarttags” />U.S. engineering giant.

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Kidde said that United Technologies, a diversified manufacturer based in Hartford, Conn., had made a revised offer of 165 pence ($3.19) per share.

In October, Kidde rejected a previous offer of 160 pence ($3.09) per share that valued the company at around 1.35 billion pounds ($2.6 billion). The revised bid is closer to the 1.56 billion pounds ($3.1 billion), that some analysts said would be needed to secure the company.

Kidde stressed that no price had been agreed between the two parties, and that it had still to recommend the offer.

“There can be no certainty that a transaction will result from these discussions,” the company’s board said in a statement.

United Technologies had previously threatened to approach Kidde’s shareholders directly to secure access to its books. United Technologies already owns about 22 million shares of Kidde, or 2.6 percent of the company’s stock.

Kidde provides fire and safety products, systems and services for industries that overlap with United Technologies’ aerospace, defense, industrial, commercial and consumer markets. The products include detection, protection, prevention and fire fighting.

Analysts had expected greater competition for Kidde, but JP Morgan analyst Tomas Melville said the revised bid was likely to see off other potential bidders.

“I don’t think it (Kidde) will attract a higher bid,” Melville said.

Shares in Kidde rose 4.5 percent to 161 pence ($3.11) on the London Stock Exchange.