DCMS say in a statement:
It is with great regret that we learn of the death of the King Abdullah bin Abdulaziz, King of Saudi Arabia.
It is requested that all flags be half-masted from 8am today until 8pm this evening.
Any other UK national flags flown alongside the Union Flag when it is at half-mast should also be at half-mast. If a flag of a foreign nation is normally flown on the same stand as the Union Flag, it should be removed.