Hipgnosis Songs Fund could be about to face a takeover battle after revealing it would be willing to accept a counter bid, valuing its catalogue of tracks from artists including Beyonce and Mark Ronson at more than £1.2 billion.

But it may not be plain sailing for the music royalties business which could see a deal thwarted by its investment adviser amid an ongoing dispute.

On Thursday, it said it had reached a deal with US rival Concord, which offered to buy the business for the equivalent of 93.2p per share, which values it at about £1.1 billion.

But over the weekend, it received a higher proposed bid from US private equity group Blackstone at 1.24 US dollars (£1) per share for the business, valuing the business at 1.5 billion US dollars (£1.2 billion).

Hipgnosis said it had reviewed the proposal and would be minded to recommend the improved deal to its shareholders should Blackstone decide to make a firm offer.

Any deal would need backing from investors to go ahead.

The takeover approaches come amid an increasingly strained relationship between the board of Hipgnosis and its investment adviser, Hipgnosis Songs Management (HSM).

HSM threatened on Monday afternoon to “use all means necessary” to defend its contractual position and interests.

It follows Hipgnosis last week calling for HSM, which is majority owned by Blackstone, to agree an orderly termination of their investment advisory agreement in order to help the deal pass.

A spokesman for HSM said: “HSM has repeatedly been blamed for many issues affecting the company which were not HSM’s responsibility under the terms of the investment advisory agreement (IAA).

“Based on extensive legal advice we are confident that the company has no legal grounds to terminate our relationship without being subject to HSM’s contractual rights contained in the IAA.

“HSM will vigorously protect its interests should the company purport to terminate the IAA.”

It also threatened to exercise a call option to acquire the assets of Hipgnosis should the songs fund decide to terminate their agreement, or take on a new investment adviser.

Merck Mercuriadis, who the launched the music fund alongside former Chic frontman Nile Rodgers, stepped down as the fund manager’s chief executive in February to become its chairman.

Mr Mercuriadis was previously the manager of world-famous acts including Sir Elton John, Beyonce and Guns N’ Roses.

The leadership shuffle meant he would have a less active role in managing the business and would focus more on its engagement with songwriters and artists.

Hipgnosis said it would continue to recommend Concord’s offer to shareholders until Blackstone confirms it wants to make a bid.

Shares in Hipgnosis were up about a tenth on Monday morning.