* Number of customers switching up 16 percent in six months
* Competition body to decide on inquiry this week
LONDON, July 16 (Reuters) - New rules making it easier forBritons to switch banks resulted in a 16 percent increase in thenumber of customers moving accounts in the first half of 2014,the body overseeing the system said on Wednesday.
The new rules, introduced last October, ensure customers canswitch accounts within seven working days, with all outgoing andincoming payments automatically transferred.
They are part of a range of measures designed to break thedominance of Britain's five biggest banks - Lloyds Banking Group, Royal Bank of Scotland, Barclays,HSBC and Santander UK - which provide morethan three-quarter of all UK personal current or checkingaccounts.
"Competition is growing as existing providers are uppingtheir offerings and challenger banks are competing to attractnew customers," said Adrian Kamellard, chief executive of thePayments Council.
However, Richard Lloyd of consumer group Which? said therate of switching was not yet enough to transform the market andcalled upon Britain's new competition body to take a closer lookat the industry.
The Competition and Markets Authority will publish thefindings of a preliminary investigation on Friday and mayrecommend a full-blown inquiry into the sector.
The Payments Council, which is responsible for the accountswitching service, said 592,695 accounts had been moved in thesix months to the end of June, compared with 511,139 in the sameperiod the year before.
The council said in April there had been a 14 percent risein the six months since the rules were introduced. (Reporting by Matt Scuffham; Editing by David Holmes)