The UK's Financial Services Authority has handed one of its largest-ever fines to a now defunct Canadian trading firm for abusive trading techniques, in a clear sign that it is clamping down on computer-driven practices it regards as damaging to domestic markets.

The FSA today said it will fine Canadian trading firm Swift Trade £8m "for systematically and deliberately engaging in a form of manipulative trading known as layering". The trading occurred on the London Stock Exchange between January 2007 and January 2008, the regulator said.