CREST went down on Friday and early on Monday before resuming service, forcing the Bank of England to delay a gilt buy-back.

"While we can confirm that CREST services have resumed, we have been responding to technical issues affecting our CREST system throughout the morning, which have been causing intermittent delays to settlement," Euroclear said in a statement.

"We are closely monitoring the situation and taking actions to resolve any issues with the utmost priority. These delays appear to relate to steps undertaken as part of the Non-Standard CREST Closure (NSCC) process invoked on Friday, September 11."

(Reporting by Huw Jones; Editing by Jon Boyle)