Living room lights flash once when switched on then turn off

[HedAix]

Hi all,
No change to electric wiring and supply and no change to the previously working light bulbs but now when I turn the 2 wall lights in my living room on (via a single switch) one of them flashes on once for half a second and then they turn off. I've tried changing both E27 bulbs, installing 1 bulb in first one and then the other light fixture to see if it's a bulb causing the trip. The flash will come from either of the fixtures but not both at the same time and neither stay on. Have tried different wattage bulbs too. Any ideas?

 

[Allysunlife]

Might be one of the wires are touching each other or loose.

 

[HedAix]

that was precisely what it was. The electrician found that a wire had come loose in the light switch somehow.