Other deals Maitland was involved with during the month included advising Abbey acquirer Grupo Santander, which sold a minority stake in the Royal Bank of Scotland to institutional investors.
It also counselled SAB Miller, which has increased its stake in Amalgamated Beverage Industries from 75 per cent to 100 per cent.
Citigate Dewe Rogerson dropped from its August top spot to second after advising on six deals in September, including work for RMC, which was a former client of Maitland, around its planned sale to Cemex .
CDR also advised National Grid Transco during the takeover of its North of England gas network.
Elsewhere in the top ten, Brunswick retained third spot, working on 18 deals worth a total of £2.5bn, including advising British Airways on its sale of a minority stake in Qantas.
Financial Dynamics slipped to fourth. FD worked on 19 deals, more than any other top-ten agency.
The volume of deals worked on by September’s top agencies was £15.9bn, down £5bn from August.