Fracking firm IGas is facing a raid on its conventional oil and gas assets by an energy group backed by US private equity giant Kohlberg Kravis Roberts (KKR).

IGas confirmed that its bondholder Trans European Oil & Gas, which is controlled by KKR, had "proposed a sale of the company's conventional assets".

Sources confirmed a Sky News report that TEOG was trying to force the sale in order to buy up the assets itself.

IGas has warned the market it expects to breach the covenants of its bonds this week, and last week held a bondholder meeting to seek a temporary waiver of the covenants.

This was approved by unsecured bondholders but rejected by a vote of its secured bondholders, now understood to be due to the opposition of TEOG, which has built up a 34pc blocking stake.

The Telegraph revealed earlier this year that IGas was on alert for a possible hostile takeover after the then-unnamed fund bought up more than a quarter of its bonds.