Slaughter and May and Cleary Gottlieb Steen & Hamilton have bagged the lead roles advising Euronext on its merger bid for the London Stock Exchange (LSE).

The firms are advising alongside each other on the bid, which is valued at around £1.4bn and could represent one of the most high profile European deals of recent years.

Slaughters corporate partners Frances Murphy and Nilufer von Bismarck are acting on UK M&A aspects of the deal and Cleary Paris-based finance partner John Brinitzer leading the team advising on European corporate, competition and regulatory issues.

Cleary's Brussels-based competition partner Nicholas Levy and London finance partners Simon Jay and Andrew Shutter are also acting.

It is the first time Slaughters has acted for the client and it is understood the top UK firm became involved through its links with investment bank Morgan Stanley.

The instruction is a blow to Clifford Chance, however, which has advised on a number of deals for Euronext over recent years and had hoped to secure a role on the bid.

The discussions come in the wake of the bid for the LSE from Germany's Deutsche Boerse earlier this month.

Freshfields Bruckhaus Deringer corporate partner Graham Nicholson is advising the LSE, assisted by corporate partner David Higgins. Ashurst corporate partner Chris Ashworth is advising Deutsche Boerse.