Mr Cuthbert's departure followed pressure from institutional investors who have become increasingly concerned with the group's dismal performance over the past two years.
Mr Cuthbert, who held the post for 10 years, is expected to receive a pounds 250,000 pay-off for loss of office. His annual salary last year was about pounds 161,000. News of his resignation came as Brent reported a slump in taxable profits from pounds 6.3m to pounds 900,000 for the first half of 1993, on sales down from pounds 63m to pounds 60m.
A loss per share of 0.5p compared with earnings of 5.3p last year. The interim dividend is being held at 1.6p but the shares fell 7p to 116p yesterday.
Brent, chaired by Lord Lane, also warned that its full-year results would be 'significantly below last year'.
The move prompted City analysts to reduce their 1993 forecasts sharply, with Jeremy Chantry of Kleinwort Benson Securities slashing his estimate from pounds 8m to pounds 5m, slightly below last year's result.
Brent's first profits warning came in January 1992, barely three months after it raised pounds 16m in a one-for-four rights issue at 120p a share. Although it boosted pre-tax profits by more than a third last year, it has since been twice wrong-footed by difficult trading conditions.
In March, Lord Lane gave a broadly encouraging statement on current-year prospects to shareholders, but two months later they were told that first-half profits would be below last year's level.
Continuing tough trading conditions have now led the company to expect the full-year result to be substantially below 1992.
Mr Cuthbert has been replaced by Keith Hutchings, Brent's former finance director, as acting chief executive.
Mr Hutchings said: 'The business has not been performing well under Mr Cuthbert, and our investors feel that he has been given a fair crack of the whip and it was time for a change.
'We have not been quick or hard enough to cut our cost base and only recently realised the need for greater efficiency.'
Yesterday's moves were accompanied by the proposed sale of Brent's electronics business, which supplies specialty products for the computer chip industry, to Cookson Group.
The deal, which amounts to pounds 24m, involves a cash payment of pounds 20m and the transfer to Brent of Cookson's subsidiary, Trafficair.Reuse content