The stock closed at 215p - its lowest since January 1991 - and trades 64 per cent below its all- time high of 599p in March 1993.
Alongside publication of interim profits, Neville Buch, the group's chairman, said: 'The full- year results will be lower than those budgeted earlier in the year.' Analysts scaled back profit forecasts for the year from about pounds 44m to pounds 34m.
Mr Buch said Blenheim's French business was experiencing a particularly harsh climate: 'Difficult trading conditions in France have recently intensified.'
Overall profits before tax for the six months to June showed a 21 per cent advance to pounds 22.1m. However, the underlying picture was not so good. Ignoring the contribution from acquisitions, Blenheim produced flat operating profit on increased turnover. Profit margins fell from 24 to 22 per cent.
Earnings per share slipped from 11.7p to 10.8p, but the company increased its interim dividend payment from 3.4p to 3.5p.
Blenheim also had a pounds 29m cash outflow in the first half of 1994. Cash flow was positive in the comparable period, boosted by a pounds 72m issue of convertible preference shares. Discounting the convertible, the cash outflow widened from pounds 15m.
Blenheim's debts also spiralled, from pounds 26m to pounds 53.4m - equivalent to gearing of 57 per cent.
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