Eric Parry's Holburne Museum rival revealed

This is one of the first images of an alternative Neo-Georgian scheme to rival Eric Parry's revised proposals to extend the Grade I-listed Holburne Museum in Bath.

This semi-submerged scheme was submitted for planning earlier this month by disgruntled local designer Martin Farrell, of architectural consultant Farrell & Company, who feels Parry's redrawn plans for a modern three-storey addition to the rear of the museum are based on 'unrealistic aspirations and wish lists'.

Parry's original design, which included a part-cobalt blue ceramic facade, was seen by many conservationists as clashing with the rest of Bath and was altered after unexpectedly being refused permission by Bath and North East Somerset Council's planning committee in July.

However, the recent tweaks to the £10 million scheme – among them a slight drop in height and the use of materials closer in colour to Bath stone – have not allayed Farrell's fears, who has drawn up his own plans without the support of the museum chiefs.

Describing his proposed 'underground option' he said: 'The basis of my scheme is on the premise of 'what would the local planning committee approve'.

'I'm amazed that the museum has been planning this for years seemingly on the false presumption that planning permission would be granted.

Farrell added: 'The museum and Parry appear to be ignorant of the politics of the situation, which to me smacks of naivety.'

In response, the museum has said that Farrell's scheme does not address its future needs. A spokesman said: 'We are five years down the line with a well-considered scheme. [Farrell] has not presented in detail how the extension would work for a functioning museum.'

Meanwhile, support for the amended Parry proposal, which is understood to reappear before the planning committee on 28 November, seems to be outshining the opposition.

A recent count of comments received on the council's website regarding the museum's plans showed around 380 postings against, but almost 650 in support of the proposals.