The Scottish Parliament is considering spending £1 million to replace light bulbs in the debating chamber.

Increasing numbers of the lights have been failing, and the type of bulbs used is about to be banned by the European Union.

Officials say the lighting system is coming to the end of its natural life - 12 years after the building opened.

Read more: SNP in lobbying row after backing Heathrow expansion

And if action is not taken, there is a risk the lights could fail and business would have to be cancelled as it could not be broadcast.

The Scottish Parliamentary Corporate Body (SPCB) - a cross-party group of MSPs who oversee the building - have discussed the problem and been told the options available.

It is understood they have accepted that they will likely have to buy a new lighting system, although no formal decision has been taken as of yet.

One parliament source said: "The lights in the chamber started to fail at a high rate - it had been two or three a year, but last year it was about 30.

"The EU rules are about to change which will make our system obsolete. In two or three years it will be impossible to replace the lights.

Read more: SNP in lobbying row after backing Heathrow expansion

"The idea is to go for a replacement system with a 25-year lifespan."

It is understood the current lights are metal halide lamps which are due to be phased out from the EU from next year on energy efficiency grounds.

And Brexit will make no difference because there is said to be only one manufacturer of the lights, based in Germany, who will likely cease production when the ban comes in.

A source confirmed the cost of a new system was expected to be just over £1 million.

The parliament building was officially opened in 2004 at a final cost of £414 million.

In 2011, the parliament said MSPs' voting consoles and microphones in the chamber had reached the end of their useful life and a new touchscreen version was installed with a bill for £280,000.

Read more: SNP in lobbying row after backing Heathrow expansion

Last year the parliament spent £500,000 on upgrading the lighting in the main public foyer after complaints that the original design by architect Enric Miralles - deliberately intended to create a "subterranean" feel - made the entrance too dark.

Lothian Tory MSP Miles Briggs said: "People will be deeply concerned and annoyed at the vast cost of replacing these lights and will want to be reassured that all other options have been thoroughly considered before this work goes ahead.

"Given the pressure on expenditure across all parts of the public sector, it is vital that the Scottish Parliament demonstrates it is offering the taxpayer the very best possible value for money."

A Scottish Parliament spokesman said he could not comment on the budget for the replacement of the lights.

But he said: "The chamber lighting system is approaching the end of its working life.

"The SPCB is therefore considering its options on whether to replace the lighting system.

"All technology ages and, in time, becomes less reliable. Replacement parts are already difficult to source and will become increasingly so."