A BBC garden makeover, which has sparked a major row in a quiet cul-de-sac, may have fallen foul of planning law.

Martin and Sylvia Johns, of Gundry Close, Chippenham, were devastated when a giant fence and a nine-foot high platform appeared in their neighbour's garden.

"The home we've made has been destroyed by the selfishness of the BBC," said Mr Johns, a property consultant.

But on Monday the row took a new twist when the BBC sent in troubleshooters to try and solve the dispute, and North Wiltshire District Council said the structure needed planning permission.

The £20,000 makeover was undertaken for the Johns' neighbour Karen Ferriman, for a BBC2 show called Small Town Gardens, presented by Rachel de Thame.

But the future of the platform is not guaranteed. A planning officer from North Wiltshire District Council called round to visit the garden on Monday and informed Ms Ferriman it did indeed require planning permission despite previous assurances from the BBC that it did not.

The homes on the development at the Pewsham estate are covered by a special condition restricting the sort of structures residents can put in their gardens.

Mrs Johns, 26, a cashier, is expecting her first baby in December.

She said she was initially excited when Ms Ferriman told them the BBC were undertaking a makeover. This week Ms Ferriman has refused to comment on it.

"At the time I thought it might enhance our garden too," said Mr Johns.

"I was told they were coming in June and July, and there would be a cube fence, but I wasn't told the details. Karen did not know what it would be like either."

He was shown plans of the proposed makeover, but lacking technical expertise, he said he could not make out what the finished scheme would look like nor the scale of the platform and fence.

"When I asked the director Mark Scott what the cube fence would be like, he just said 'Wait and see.'" said Mr Johns.

The makeover team began the transformation about three weeks ago, in the sloping garden behind Ms Ferriman's house.

The Johns waited excitedly to see what might emerge but when they came home from work last Tuesday the realisation sank in.

"I thought my god, it's horrible," said Mr Johns.

"It hit us really hard. I went round to see Karen and told her I really was not happy with the shape of the fence, and could they adjust or change it. She said no and would not discuss it."

Mr Johns called producer Vanessa Jackson to protest about the fence, and she said she would arrange a meeting.

"Mark Scott came round on Tuesday evening and I showed him the view of the fence from the bedroom window. I told him we couldn't live with it," said Mr Johns.

"He admitted it was a bit big. It makes my garden look like a prison camp. They have ruined my garden to create their garden."

But Mr Johns became even more angry when the platform went up and he realised how tall it was.

"It overlooks our garden and ruins our privacy," he said. "You assume a designer will consider the surroundings when they design a garden."

Mr Johns demanded the work be stopped but the BBC refused and Mr Johns took his story to the press.

A series of phone calls to the BBC culminated in a secret 90-minute meeting at the Johns' home on Monday, with the director and producer.

Mr Johns said finally they had thrashed out a solution to the problem and reached a compromise.

They promised the BBC they would not divulge details of any amendments to the makeover, but they are waiting to see if they stick to their word. "If everything happens as discussed, then I will be satisfied," said Mrs Johns.

But the BBC are not out of the hot water yet they still have to lodge a retrospective planning application for the platform.

A spokesman for the BBC said: "As always with our gardening programmes we keep local residents fully informed of our plans and are always happy to discuss in detail any concerns.

"In this instance the neighbour had been shown the plans for the garden and was fully briefed in the designs prior to commencement on the garden and he did not raise any concerns at that stage."