LONDON (Reuters) - Royal Bank of Scotland is confident it will be able to remain a player in the debt capital markets despite a cap on its activity, a bank spokesman said on Tuesday.

RBS is not allowed to rank any higher than five in the global all-debt league table for the next three years, following a ruling by Europe's competition watchdog.

It is one of a number of measures imposed by the regulator to limit the scale of the bank's balance sheet and activities so that it does not gain an advantage from state help it has received.

The all-debt league table includes global bonds and syndicated loan issuance and excludes short-term money markets and self-led bond issues. RBS is currently in sixth position in this ranking of debt activity, and was in fifth place at the same time last year, RBS said.

"Historically we have been able to service a large number of clients while never being ranked higher than 5 for all global debt, so I do not believe that this restriction impacts our ability to deliver our strategy," the RBS spokesman said.

The use of an aggregate such as the all-debt league table will not have much of an effect as it will still allow RBS to target its key markets of continental Europe and the UK, according to one head of debt capital markets at a European competitor.

(Reporting by Alex Chambers; Editing by Erica Billingham)