Mark Woolley, 36, from north London, has been convicted of murdering television costume designer Elizabeth Sherlock.
Mrs Sherlock was killed when she was thrown from a car and then run over after her handbag was snatched.
The jury has not decided its verdict in the case of Jackie Moorehouse - also accused of murder - and is continuing its deliberations.
Self-confessed drug addict Woolley and Moorehouse had denied murdering 42-year-old Mrs Sherlock who jumped on the bonnet of their car as she chased the handbag thieves.