LONDON -- Takeover activity in Britain has picked up markedly in the past two weeks, and there is increasing interest in possible U.S. acquisitions -- inspired in part by the cheapness of the dollar.

Michael Stallibrass, head of mergers and acquisitions in Shearson Lehman Bros.' London office, said the October stock market collapse shifted merger activity from smaller entrepreneurial companies, which financed acquisitions with stock, to larger, cash-rich British conglomerates.

"People are saying, 'Here is an opportunity to make U.S. acquisitions,' " said Stallibrass. "We are doing more preparatory work right now than we were three months ago. In my experience, you don't do a lot of preparatory work without getting deals at the end of the day."

Richard Kelly, head of mergers in First Boston Corp.'s London office, said his firm was also experiencing a resurgence of interest from cash-rich companies. First Boston advised on the first significant British acquisition of a U.S. company after the stock market collapse -- English China Clay's takeover of J. Shiely for $73 million.

"It may take one large company with a demonstrable record in making acquisitions to break the ice," he said.

Analysts speculate that Hanson Trust may be the firm most likely to play that role. Hanson is sitting on a cash mountain worth $5.4 billion at today's exchange rate, the best sterling rate in five years.

"We see this as a time for real opportunities, with prices substantially down on what they were," said Martin Taylor, a director of Hanson, which in August bought New Jersey-based Kidde Industries.

Other cash-rich companies tipped as possible buyers in the United States include BTR, which bought electronics and defense manufacturer Stewart-Warner Co. this year, and GEC, which recently bought avionics firm Lear-Siegler Inc.

Many European companies and analysts are sticking to favorable long-term views of the U.S. economy.

"The U.S., in anyone's definition, is still the largest and the fastest-growing chemical market in the world," said John Dewhurst, acquisitions manager for Imperial Chemical Industries (ICI), who bought Stauffer Chemicals earlier this year.

"We plan on a long-term basis, and our desire to be bigger and wider in the U.S. hasn't changed," he added.

But Richard Kalms, spokesman for Britain's largest electronics retailer, Dixon's, was much more pessimistic, saying that his firm's aggressive shopping for acquisitions has been suspended for the time being.

"The consumer durable market worldwide is looking very dicey, and at the same time our share price took a terrible knock," he said. "For us this is a time of wait and see."

British companies and European companies generally did not go as heavily into debt during the bull market as did American firms. A recent study by London brokers Phillips and Drew said that the amount of leveraging by British companies is substantially below levels of 10 years ago, while cash on hand has increased to 16 percent of assets.

Tim Plaut, an analyst at Warburg Securities, said West German companies are even more heavily capitalized than British firms and are more likely to move into the United States in 1988, driven by the relatively stronger long-term growth prospects there.

"With population falling by a quarter of a million a year, the German economy is fundamentally ex-growth," he said. "We have seen U.S. acquisitions by the major German chemical companies and one or two nontraded companies like Bertelsmann, but major industrial sectors in Germany like machinery and electricals have been conspicuous by their absence.

"It will come when the current scenario sorts itself out, when more stable values for currencies and equities start to emerge," he said.

The resurgence of takeover activity in London has included a battle for MK Electric, a fight that began when RTZ offered $370 million for the company. The bidding turned into a multinational struggle when French firm Legrand and West Germany's Siemens made competing bids.

Siemens on Thursday pulled back its bid, but the other two are still on the table. Other deals include Allied-Lyons' purchase of 49 percent of liquor firm Hiram Walker for $1.03 billion, and another multinational struggle between British Airways and Scandinavian airline SAS for control of small British carrier British Caledonian.