Dive, dive, dive...Marconi shares fell to a 26-year low yesterday after the telecoms equipment manufacturer warned the events of 11 September will cause it to fall short of first-half targets. In a statement to the US Securities and Exchange Commission, the company said the terrorist attacks on New York and Washington had "increased the general uncertainty in [its] markets". Marconi shares fell to 13p from 18.25 - almost 30 per cent - on the news. The company's shares peaked at over 1200p last year. Analysts last week said shares in Marconi were effectively worthless.