MSPs have complained about the poor signal in many parts of the parliament complex ever since it opened in 2004.

But now small aerials are to be installed in strategic locations to ensure better coverage for politicians making and receiving calls on their mobiles.

Work on the contract began this week. Initially it will mean a better signal for Vodafone – the network the parliament is signed up to – but it is hoped other suppliers will be added soon. MSPs today welcomed the prospect of better mobile reception, but blamed the design of the £414 million building for creating a communications "black hole".

Independent Lothians MSP Margo MacDonald said the difficulty in getting a signal was almost certainly due to the use of so much concrete and steel in the building and the decision to site the parliament in "a wee hollow".

On the £50,000 cost, she said: "It's absolutely ridiculous – as usual. But the self-indulgent nature of the architecture and design of the building has been commented on before."

Edinburgh Pentlands Tory MSP David McLetchie said: "This is a lot of money to sort a fault that should never have arisen if the design had been up to scratch.

"But one hears of owners of buildings being paid to put up mobile phone masts. Perhaps the parliament should investigate that, then we could improve things not just for us but for people in the surrounding area – and we would be quids in."

Problems with mobile reception were reported even before MSPs moved into the new parliament in August 2004 and officials have been trying to sort out the situation ever since.

In a report to the cross-party Scottish Parliamentary Corporate Body, which is in charge of the Holyrood building, parliament chief executive Paul Grice said progress on solving the problem had been "slower than any of us would have liked".

A parliament spokeswoman said: "Work is being undertaken to resolve the issue of poor reception in certain parts of the building with the installation of the smoke-detector size pico-cells to boost reception."