The clues were all of the "normal" type, so there were no messages being generated from the clues themselves. Instead, solvers had to deduce the unclued lights and the sequence they represented.
These were the most recent constituencies of the last five ex-prime ministers in reverse chronological order:
David Cameron WITNEY
Gordon Brown KIRKCALDY and COWBENBEATH
Tony Blair SEDGEFIELD
John Major HUNTINGDON
Margaret Thatcher FINCHLEY
Finally, solvers were required to highlight the the most recent addition of MAIDENHEAD (Theresa May), which was hidden on a diagonal in the grid.