The index closed 29.2 points lower at 2,348, although five points of the fall was accounted for by seven constituents going ex-dividend.
The performance on the first day of the account indicated a market becoming increasingly wary of being sucked into any more false dawns on the economy. Dealers were also uneasy about expectations of more gloom from today's quarterly survey from the CBI, and the possibility of increases in mortgage rates by some building societies.
Negative reaction in Tokyo to Japan's half-point cut in the discount rate to 3.25 per cent also caused some concern. Even a steady opening on Wall Street failed to lift the market's mood.
Wellcome shares barely managed to hold on to their 800p striking price, losing 25.5p to 800.5p.
Market volumes were swelled by BZW's share swap scheme involving Wellcome's issue, but there was confusion in the morning about trading levels because of a systems failure at the investment bank.
Just 16 FT-SE stocks escaped being marked down, but gains were a few pence at best.
Gilt-edged stocks, however, were steadier with falls contained to a sixteenth at the longer end.
Total volume in Wellcome alone was put at 23 million at the close, although the underlying figure was probably higher with numerous delayed trades going through in late trading.
In all, the market turned over 564 million shares, bolstered to some extent by BZW's dabbling in up to 450 stocks for investing some of the proceeds of the Wellcome sale.
Banks were active ahead of this week's start to their interim reporting season. TSB was initially buoyed by weekend press reports of a bidder - probably Continental - in the wings.
Stories that a German bank might be ready to pounce were soon discounted, however, and TSB ended the day all-square at 138p.
Banks were generally weaker on concern over bad debt provisions. Lloyds, due to raise the reporting curtain on Friday, gave up 5p to 404p. Among the other clearers, Barclays shed 2p to 305p, and National Westminster lost 3p to 311p.
HSBC Holdings, weak of late, came under more pressure, and eased another 10p to 319p.
Reuters continued to suffer from last week's cautious trading statement, dropping below pounds 10 with a 26p dip to 985p.
ICI, due to announce interims on Thursday, was clipped 30p to pounds 10.68.
One notable exception shining out from the day's gloom was Lasmo, which clawed back all of Friday's deficit to close 15p higher at 133p. The price, though, is still a long way adrift of the year's high of 263p.
Yesterday's gain was due in part to SG Warburg's belief that the shares are undervalued compared with asset backing.
There were also faint bid rumours incorporating the name of Shell, and expectations that the company's interim results tomorrow will match analysts' forecasts.
Euro Disney continued to feel the backlash of last week's loss warning, although the shares closed off the bottom at 973p, down 22p.
Jangled nerves elsewhere in the leisure sector pulled Owners Abroad down 2p to 68p, and Airtours by 4p to 220p.
Bass, though, shook off Friday's downgrading by Cazenove, gaining 3p to 525p. And Greene King's humiliating bid defeat at the hands of Morland was put aside with a 8p mark-up to 475p. Morland, however, retreated 2p to 418p.
Amstrad dropped 2.5p to 26p in the wake of last Thursday's warning of larger-than-expected losses, and Friday night's sudden departure of its finance director.
The construction sector was undermined by the Building Employers' Federation predicting that 40,000 jobs could be lost this year, and output could fall in the second quarter.
Among the casualties were MJ Gleeson, down 17p to 758, Taylor Woodrow, off 3p to 56p, and Wilson Bowden, which fell 12p to a 1992 low of 290p.
Wilson moved quickly to quash rumours that the company was having problems, saying that the share price fall was due to the market reassessing where housebuilders were going. Gerald Berwick, finance director, added that the company's finances were 'absolutely rock solid'.
Share prices were in retreat throughout the day's trading session, with many losses extending to double figures. The FT-SE 100 index declined by 29.2 points to 2,348, while the narrower FT 30 lost 22.1 to 1,767. Volume trading, buoyed by the Wellcome share issue, topped 560 million. Gilt-edged stocks were largely unchanged.
Shares in Fyffes, best known for bananas, found favour yesterday as it announced an agreement to take a 50 per cent stake in Saba Trading, a fruit and vegetable distributor owned by Axel Johnson, the Swedish trading company. The stake is being acquired for Ir pounds 51.7m (pounds 48m). Fyffes, ahead 4p to 80p, also has options to acquire the other 50 per cent holding.
A profits warning by Cliffords Foods wiped a hefty 48p off the ordinary shares to 410p and 25p from the 'A' to 123p. A delay until July in obtaining increases in the selling prices of milk supplied to major retailers has hit results for the first half of 1992. Costs of modernising a dairy have also taken their toll. The company expects, however, to maintain dividends.