That's caused resentment from some local communities unhappy at having large sites on their doorstep.
And we heard from the housing minister Yvette Cooper.
We need to provide more sites, we can't do it quickly however. 
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Here's what our reporter Sarah Campbell found when she visited Cottenham, a place experiencing conflict between residents and travellers:
In March this year, the people of this Cambridgeshire village refused to pay their council tax. It was the only way they felt the authorities would take their concerns over a neighbouring travellers camp seriously.
There had been a travellers camp just outside the village of Cottenham for 40 years. Then early last year that land was bought by Irish Travellers who bought more land and only retrospectively applied for planning permission.
The possibility of hundreds more Travellers on their doorstep led local people to set up a nationwide campaign group demanding action.
The situation at Cottenham is not unique. The number of what are called unauthorised developments where the land is privately owned but permission to live on it hasn't been granted...is nearing 2000.
Legislative changes in the early 90's took away the statutory duty on local councils to provide gypsy and traveller sites. Instead they are supposed to identify suitable areas and work with the communities to purchase and develop them.
In practice, this just hasn't happened. In the majority of cases, where land is bought by an individual and planning permission sought...it will be turned down.
Local authorities believe they are being made to shoulder responsibility for what should be a national issue.
All those involved await the results of a Central Government review into the issue, as well as the widescale changes to planning policies due to be published at the end of the year.
In evidence to the select committee inquiry the Government predicts thousands more pitches will be needed. But where they will be is a question very far from being answered. 