A little-known investor in AGL Energy has publicly urged the board to abandon its “flawed” demerger plan and bring forward the closure of its coal power stations to 2030, in a move that could play into the hands of the $5 billion takeover approach by Brookfield and Mike Cannon-Brookes.

The value of AGL shares could surge up to 60 per cent if the company scrapped the demerger and pursued an accelerated transition to phase out coal, London-based Snowcap said in a letter emailed to chairman Peter Botten and CEO Graeme Hunt, and released on its website.