Buckingham Palace is to be illuminated at night for the rest of the Queen's reign.
From today, the front of the palace will be lit with 59 LED lights from sunset until 11pm.
The move follows concerns from the tourist industry that visitors could not clearly see the famous landmark after 4pm during the winter months. But the decision received mixed responses.
While tourism operators welcomed the move, environmental groups labelled it disappointing and unnecessary.
The Queen is said to have agreed to the scheme after reassurances that the lighting would not disturb staff who have bedrooms at the front of the palace.
A team was set up to look into the idea, and the experts who lit up Edinburgh Castle were called in to offer advice.
Following consultation, electrical company Philips was used to create the environmentally friendly, cost-efficient lighting.
The state-of-the-art LED lights, in a warm white colour, are low maintenance and less intrusive than regular lighting. However, environmental organisation Greenpeace said it was "disappointed" at the decision to illuminate the palace.
Spokesman Charlie Kronick said: "These lights are going to blaze away until the end of her reign, and the way she's going, that could be a very long time, probably long enough to see the catastrophic effects of climate change strike our country and the wider world.
"Making your house look like Blackpool Tower all year round is no example to set to your nation."
London Assembly Green Party member Darren Johnson said there was "no real need" to light the historic landmark.
He said: "Given the need to reduce energy and tackle climate change, we should be turning lights off - not switching more on.
"The Royal Family seems to have a habit of urging us all to be more environmentallyfriendly and then doing the
exact opposite themselves. I appreciate that they are trying to find energy-efficient methods but plans to floodlight the Palace when there is no real need sends out a poor message to Londoners."
Lights on the ground will highlight the three portico columns, while the rest will illuminate features between the windows.
The installation has cost £37,000, which will be paid for through grant-in-aid.
A spokeswoman for Visit London said they believed the illumination would have a "positive impact" and benefit visitors.
"We're pleased to hear that Buckingham Palace is going to be illuminated in a thoughtful and responsible manner," she said.
"It is one of London's most significant buildings, and not only will this move extend viewing times for visitors during the winter evenings when it's dark after 4pm, but it will also have a positive visual impact on the whole area surrounding the Palace."