Monavon Construction pleaded guilty to two counts of corporate manslaughter and to breaching Section 3(1) of the Health and Safety at Work Act at the Old Bailey on 9 May. Sentencing took place on 27 June.
British Transport Police officer Gavin Brewer, 32, and television producer Stuart Meads, 34, had been out drinking together. The pair were seen on CCTV walking along a street in the early hours of the morning on 19 October 2013.
They started arguing and one pushed the other against the building site perimeter hoarding that was on Netley Street at the junction with Hampstead Road. The hoarding gave way and Brewer and Meads fell head first, 4 m down an uncovered lightwell that was part of a basement flat under construction by Monavon.
The two men sustained fatal head and neck injuries and were pronounced dead at the scene.
Oliver Glasgow, QC, prosecuting, said the hoarding was not of sufficient height or strength, and for at least two months there had been no cover on the lightwell. He said there were many occasions in the days leading up to the accident when access to the site was unprotected.
The Metropolitan Police and the Health and Safety Executive launched a joint investigation and found that the hoardings had been fixed in such a way that only negligible force would have been required to make them give way.
Sentencing, Judge Paul Worsley QC said the deaths were an "accident waiting to happen" and "wholly preventable", Associated Press reported.
"This was not an isolated incident -- the court must mark this by fines that I accept are very heavy," he said.
Monavon, which has an annual turnover of around £500,000, was fined £250,000 each for the deaths of Brewer and Meads plus £50,000 for the health and safety breach to be paid in two years. It was given six months to pay £23,653 in prosecution costs.