Allen & Overy (A&O) has advised European investment bank Schroder Salomon Smith Barney (SSSB) on behalf of Shell Resources in its takeover of Enterprise Oil. The takeover of the leading independent energy company has been a crucial testing ground for the Financial Services and Markets Act 2000. The new legislation, which was enforced in November 2001, was introduced as a new civil offence for market abuses. However, there is huge uncertainty in the City over the extent to which the act is relevant in transactions, given that so far it has been relatively untested. The new legislation has placed businesses on the defensive by providing sanctions against market abuses for misuse of information and rendering insider dealing and market manipulation as civil offences. A&O partner Patrick Speller, who led the deal, said it was necessary to analyse tried and tested principles in light of the new legislation. "The legislation affects financial promotion and a takeover is a form of financial promotion because people are selling shares," he said. Enterprise was advised by long-term adviser Herbert Smith, led by partners Stephen Wilkinson and Gavin Davies. The merger brings to an end an intense phase of high-profile negotiations by Herbert Smith, which started on 8 January when it advised Enterprise on a takeover bid by Italian oil and gas company Eni. The deal finally fell through because Eni's purchase offer was too low. Herbert Smith said the £4.3bn deal was simplified because it involved a cash offering rather than a share offering. Slaughter and May advised Shell and negotiated successfully the high 725p per Enterprise share at a time when oil prices topped $28 (£19.50) a barrel. Eni's offer only just topped Enterprise's share value of 620p. Slaughters corporate partners Nigel Boardman and Richard de Carle led on the deal. Rothschild and Morgan Stanley provided financial advice to Enterprise's directors.