London - Britain's financial watchdog says firms in the UK will be required to record cellphone conversations of their investment bankers and traders in a bid to tackle insider trading and market abuse. The Financial Services Authority says existing rules requiring investment firms to tape all landline phone conversations and e-mails involving client orders or arranged transactions will extend to work cellphones starting next year. The watchdog said Thursday the measure will provide an extra source of evidence to counter market abuse and promote cleaner markets. Spokeswoman Sarah Bailey said the rule will only apply to business cellphones issued by firms, not personal ones. The messages will be stored for six months. Firms that do not comply with the rule can be fined.