There were angry scenes at Swale House when the developer behind the town’s Morrisons’ store applied to renegotiate its planning permission terms.

Essential Land had previously agreed that 30% of the homes built close to the supermarket would be affordable housing.

It also shook hands on deals to provide up to £215,000 to support heritage initiatives and make a contribution of nearly £500,000 to Kent County Council for primary and secondary schools.

This was as part of a section 106 agreement in which local authorities give planning permission in return for developer contributions.

These usually includes cash, work or materials towards local community initiatives such as housing, schools, roads, arts and culture.

Essential Land was given the nod to build the supermarket and housing in 2012 as long as it honoured the S106 agreed with Swale.

However, appearing before the council’s planning committee, company partner Martin Bellinger, argued the deal was “burdensome”.

He said that without changes, the development would not be viable.

The firm is set to build 150 homes near the supermarket and now wants the amount of affordable properties – for social housing etc – to be cut to 10%.

It also says any money towards heritage schemes should be dependent on the profits made from the housing development. But it will honour its initial arrangement regarding the contribution to schools.

The proposed changes outraged councillors, with Labour’s Roger Truelove saying: “I am absolutely apoplectic with anger about this – the council is losing £250,000 or more.”

He pointed out that two years previously, the developers were happy with the S106 and said he believed the “council [had] allowed itself to be duped”.

Cllr Bryan Mulhern (Con) said it was “totally disappointing”.

Cllr Angela Harrison (Lab) said the council’s policy was to provide a minimum of 30% social housing in developments and that the current situation had arisen from “Swale [being] seen as a soft touch” by developers.

Prior to the meeting, Essential Land underwent an independent viability assessment and the resulting report was submitted to planning officers.

They subsequently advised the proposed alterations be accepted as per government guidance stating S106s should be renegotiated to get more housing built.

The decision on allowing the changes was deferred until a later date allowing more time for negotiations.