Sources close to the company say Simon Duffy, former chief executive of NTL, is to become non-executive chairman.
As well as being a former finance director of Orange, the European mobile operator, Mr Duffy was chief executive and deputy chairman of World Online, a Netherlands-based internet service provider whose flotation in 2000 is remembered by many as the height of the dot-com bubble.
Cadogan will join two other London-listed companies developing gas fields in Ukraine, one of which, JKX, it is set to become a constituent of the FTSE 250 index.
The company is based in Kiev but most of the board members are British. It is backed by investors including the private equity funds of JPMorgan and Deutsche Bank.
Ukraine has Europe’s third-largest gas reserves – on a par with the Netherlands and behind only Russia and Norway – but lack of infrastructure means that it is a large net importer.
Cadogan has benefited from the sharp rise in energy prices since it bought its first assets in December 2005.
Cadogan has little production today, but the first of its main fields is expected to come on stream later this year. The company’s brokers are UBS and Fox Davis.




