THE chief executive of the London Stock Exchange has said he will stay on at the group if, as widely expected, its £21 billion merger with Deutsche Borse collapses.

Xavier Rolet, who had been expected to retire following the completion of the deal, said he may be "back in the seat" as the deal looks set to fall through due to competition concerns.

Speaking alongside LSE's full-year results, Mr Rolet said the group "continues to work hard on its proposed merger with Deutsche Borse", but in the same breath added: "It looks like my retirement has been postponed."

The official end could be confirmed at the beginning of April, when the European Commission will rule on the deal.

The news comes following LSE's decision on Sunday to reject the commission's request to offload its 60 per cent stake in the Italian trading platform MTS.

The exchange operator reported a fall in profits from £357.1 million to £192.9m for 2016 as it was stung by costs associated with the deal and higher taxes.

Total income climbed 17 per cent to £1.7 billion.

On the threat of Brexit to the LSE, Mr Rolet said: "Our group is global and our customers do not look at their businesses in a national way.

"We don't know what Brexit will look like, but the EU has equivalency with the US and Asian countries."

Mr Rolet has previously warned that the UK's powerhouse financial sector would face heightened risk and an exodus of thousands of workers without certainty over Britain's Brexit deal.