The knack for invention: Britain hasn't lost its touch

In my home in Surrey stands a 16-inch color TV set which has just flashed onto its screen evidence that Britain, despite troubles and recession, remains a world center for new ideas.

I picked up a remote-control handset the size of a pocket calculator, and used British electronic wizardry to summon to the screen in quick succession: news headlines, including the Labour Party claiming that the Social Democratic-Liberal alliance is slipping behind and that Japan's Nissan Auto Company is still undecided about building a plant here; a report that international athletes will compete in the Welsh Games July 9-10; and latest arrival times for Heathrow Airport.

A few more pushes of the button brought on a recipe for tarte a l'orange; today's crossword puzzle and the answer to yesterday's; a weather report in Vienna; a selection of children's jokes: (Q. ''How do you get milk from a cat? A. Steal its saucer.''); and classified car advertisements.

My TV set, in fact, has become an electronic newspaper, thanks to a process called ''teletext.''

British engineers were the first in the world to discover (in 1972) how to transmit data between each of the successive individual pictures that together form the conventional TV picture. Now the British Broadcasting Corporation says that visitors from almost 100 countries, including the United States, have come to London to see how its system, Ceefax, operates.

A similar system called Oracle operates on Britain's two commercial channels. Britain has more teletext sets in private homes than any other country - about 1 million, covering 5 percent of total households. Sales soared 168 percent in 1982. Executives at Oracle predict there will be 3 million sets by 1985 and possibly 17 million by 1990.

The US is now racing to catch up. Several limited trials are under way in such cities as Columbus, Ohio, Cincinnati, Houston, Dallas, San Diego, Pittsburgh, and Omaha.

Teletext is, in fact, an example of how ideas first discovered in Britain continue to influence modern life - despite Britain's industrial decline and its continuing search for a national identity and role since World War II. British laboratories, think tanks, universities, institutes, and workshops are still rich with individual inventiveness.

''In terms of our population and size, we do very well in Nobel prizes and in other ways,'' comments David Fishlock, science editor of the Financial Times newspaper in London.

''We have a flair for one-off (individual) inventions,'' says Graham Clayton, editor of the BBC Ceefax service. ''The Japanese do assembly lines better. Our strong point is the original idea.''

Where Britain lags, however, is in its ability and willingness to risk capital and roll up its sleeves to apply and market new ideas.

''We just don't have the financial resources,'' says Humphrey Metzgen, sales and marketing controller of Oracle Teletext Ltd., which sells advertising for the commercial TV teletext service on Channels 3 and 4.

The Thatcher government has tried to persuade bankers and financiers to unlock more venture capital. So far however, despite Britain's urgent need to export more competitive goods, success has been limited.

''We, and some other parts of Europe, are older societies, and we no longer have the entrepreneurial drive that America possesses in such abundance,'' Mr. Fishlock says. ''We have been active in biotechnology - genetic engineering -research, but in the last five years we have produced only about 20 companies actually following through, whereas the US has about 200.''

All but one source contacted agreed that the enterprise and drive that created the first Industrial Revolution were still widely lacking in Britain.

The notable exception was Clive Sinclair, the multimillionaire innovator whose latest success is the first microcomputer to sell here for less than (STR) 50 (about $82).

What makes teletext possible is the black line, invisible to the viewer, which separates each of the successive TV images transmitted through the air. (Britain does not yet have cable, though teletext works on cable equally well.

This ''vertical blanking interval,'' as it is called, is itself made up of a number of lines. British engineers at the BBC and commercial television companies discovered a way of loading data electronically into those lines.

A decoder built into a set unscrambles the signals. All four channels here (two BBC, two commercial) transmit a total of almost 1,000 numbered ''pages'' or screens of information in several colors.

News headlines and four-to-five-paragraph stories are continuously updated by small editing staffs, using BBC and Independent Television (ITV) news resources worldwide. Each station broadcasts the cycle of its own ''pages'' continuously for as long as it is on the air, at the rate of about four screens per second.

On my handset I punch button ''1'' for BBC Channel 1, then a button marked ''text.'' I punch in the number ''100'' for the general index, find the number of the item I want, punch that number on the handset, and wait a few seconds.

At the top of the screen unroll the numbers of pages being broadcast. When the page I have ordered arrives, it is ''caught'' and pops onto the screen. I can punch a ''hold'' button to keep it there for study.

I can split a ''page'' in half and enlarge each half for easier reading. A ''mix'' button enables me to see the TV picture on that channel behind the writing.

A number of transmission methods have been developed, and are fighting for markets.

Britain's system dominates European tests so far. The French have a method called ''antiope.'' Canada has its own ''telidon.'' Yet the US may settle on yet another type.

Teletext has taken off here because many new sets come with decoders built in , at reasonable prices. About 70 percent of all sets here are rented, not bought. Aided by government subsidies aimed at encouraging teletext, deposits and monthly rental costs have fallen to within $2 a month of conventional sets.

Research indicates that each teletext user dips into the ''pages'' four or five times a day for a total of about 20 minutes, mainly in the evening.

Teletext continues a centuries-old tradition of British innovation.

The original Industrial Revolution was made possible by the work of three Scots: James Watt (inventor of the steam engine), James Naismith (the steam-hammer), and William Neilson (the blast furnace).

In the last century, Alexander Graham Bell invented the telephone in the US just six years after emigrating from Scotland. James Clark Maxwell is regarded as a father of electronics theory. And more recently, Godfrey Hounsfield helped to pioneer the new field of computerized three-dimensional X-ray scanning, and British scientists have been prominent in physics and radio astronomy.

Between the first year of the Nobel prizes (1901) and 1980, British scientists won 20 Nobels for physics, 22 for chemistry, and 19 for medicine.

In fact, inventors here have been so prolific that when the Scottish Development Agency produced a television advertisement listing some of the inventions to emerge from Scotland alone, the British Independent Broadcasting Authority in London at first blinked in disbelief.

The IBA, which examines British television ads for accuracy, ordered documentary evidence for each invention. Researcher Elspeth Wills in Glasgow produced it.

Ticking off some of her list, she mentioned: the reflecting telescope (a claim disputed by the English who say Isaac Newton beat James Gregory to it), the separation of helium gas (Sir William Ramsay), the first demonstration of television (James Logie Baird), the first logarithm tables (Sir John Napier), decimal notation, paraffin, the color photograph (James Clark Maxwell), asphalt, the pneumatic tire, neon light, the original clutch, and the cloud chamber used for detecting subatomic particles.

Meanwhile, the British invented another system that allows viewers to ''talk back'' to their TV sets through telephone lines. The ''videotext'' process lets them shop from catalogues, buy vacation tickets, or make bank deposits.

The British service, called Prestel, is operated by British Telecom, the newly private arm of the British telephone system. But it has had a slow start. Spokesman Peter Wynn Davis said that since 1979, Prestel had gained 25,000 subscribers. About 4,500 were private individuals, and 21,500 were companies, including a large proportion of sales organizations and travel agents.

In the US, Dow Jones News Retrieval, H & R Block's CompuServe, Reader's Digest, and Prestel are using phone lines for test programs offering banking and other services.

Tomorrow: The changing Britain -- and the challenges -- that face whatever government is elected June 9.