Harrogate council had rejected the mast application

The hearing comes after the High Court overturned a planning inspector's decision to reject the plans.

The judge's interpretation of current guidelines is being challenged.

On Thursday, judges reserved judgement after hearing a day of submissions on a similar case involving a mast near a school in Winchester, Hants.

Two-day hearing

In the High Court in June, Sir Richard Tucker ruled that the Harrogate mast - proposed by T-Mobile, Orange and Hutchinson 3G - met current safety guidelines.

He said that the plans did not give rise to "actual danger", even though there was a "perception of risk" among the public.

He quashed the planning inspectorate's decision to reject the plans, saying that guidelines were concerned with "actual rather than perceived health risk".

Campaigners fear his decision will allow companies to ignore health fears and erect masts on sensitive sites in the future.

The hearing could influence up to 12,000 similar cases involving 3G mobile phone masts across the country.