John Welford loved playing little games with ATC staff. I recall one day in July, 1970 when I was acting as Briefing Officer in Heathrow AIS (in the old Queen's Building).
Capt.Welford arrived to collect the daily Briefing Notes and realised that there was a new ATCA with me in AIS. He winked at me, and in his usual bellowing voice, asked for the latest Snow State for Malaga. I sent the new lad to find the SNOTAM file, which, of course was empty (temperature at Malaga was in the high 30's C.). New lad comes back to Welford and says "Sorry, the file is empty", whereby the dear Captain stormed off, muttering about the incompetence of the system and that he hoped he would not have to divert from Malaga due to the runway conditions.
It took a few minutes for the new lad to realise that he had been duped by one of Heathrow's "characters"...with a little help from me..!