Lotus suffered a £42.6m pre-tax loss last year due to production difficulties and restructuring costs.
The loss for the UK sports car and engineering group 80%owned by Proton of Malaysia was on turnover of just £144.7m in the year to March. It compares with a pre-tax profit the previous year of £14m on sales of £137m.
More than half the loss - £22.1m - has been put down to delays in introducing models and modernisation of manufacturing facilities. The remainder relates to research and development costs.
The company said it had been too ambitious in seeking to virtually triple production in one year to 6,000 units, using untried manufacturing facilities.
Half the output was intended to be of the new Lotus Elise, the other half the Vauxhall/Opel Speedster that Lotus has designed and is building for General Motors. One car is six months late and the other nine months.
The losses were compounded by restructuring, which has seen more than 300 of Lotus's 2,100 jobs lost.
The latest registration figures, published by the SMMT, also show that to the end of September Lotus sales have fallen 42% this year compared to the same period in 2000.