The European Commission has blocked the £24bn tie-up of the London Stock Exchange and Deutsche Boerse, killing off a merger it said would create a "de facto monopoly in the markets for clearing fixed income instruments".

Plans to create Europe’s largest exchanges operator were finally squashed by Brussels on Wednesday, with EU Commissioner Margrethe Vestager saying that the tie-up "would have significantly reduced competition" in the "crucial area" of fixed income clearing.

"As the parties failed to offer the remedies required to address our competition concerns, the Commission has decided to prohibit the merger," she said.

The decision, which ends the pair's third formal attempt at a merger since 2000, will also mean that the proposed sale of LSE's French clearing house LCH Group to Euronext - a deal agreed to appease competition concerns - will no longer go ahead.

Both sides released statements on Wednesday morning saying that they regretted the decision but were confident in their prospects as standalone businesses.

This outcome had been widely expected, with the LSE admitting last month that its refusal to sell its Italian bond trading platform MTS to appease competition concerns now meant the deal was unlikely to receive approval.