DEFA says there are commercial considerations
Island mobile phone providers do not legally need to share masts, the House of Keys has been told.
Although, the Department of the Environment, Food and Agriculture always encourages operators to share, they are under no obligation and it is not always viable.
DEFA Minister Geoffrey Boot said a range of factors, including commercial considerations and line interference, meant it wasn't always possible.
Mr Boot also confirmed his department had decided not to write to operators asking where the masts are sited around the Island.
North Douglas MHK David Ashford last autumn asked for a list but Mr Boot said DEFA had been advised by the Communications Commission that commercial and financial sensitivities prevented those details from being made public: