The Heathrow electricity substation explosion that shut the airport and caused chaos among travellers today, is being blamed on the Russians and nothing to do with equipment failure due to lack of investment by the airport operators, MI5 have claimed.

An MI5 spokesperson told FNN:

This has the fingerprints of SMERSH all over it. Or it would have if anything was left after the fire.

We have located a picture of this substation in a batch of papers, known internally as THE IPCRESS FILE, that were stolen from the Russian Embassy in London in 1962 by our master spy, Harry Palmer, formerly a Corporal in the Army Catering Corps.

FNN has also learned that two FSB colonels were caught on local CCTV lurking around a nearby fish and chip shop just before the blast. The owner told us that they feasted on pickled eggs, mushy peas and gherkins before disappearing into the night complaining of stomach pains.

It is thought, by experts, that a disruptive substance - probably Novichok, a favoured Russian poison - could have been mixed into the substation's oil tank causing a massive explosion. Unfortunately all the oil burned up in the fire so there is no way to prove if the oil was in fact contaminated.

Equally unfortunately both the FSB colonels appear to have been killed in the blast as there is no trace of them, which means there is no-one able to corroborate the story that this was yet another case of Russian interference on British soil.

A piece of a South Western Railways train ticket from Salisbury to Waterloo was located at the scene, which also points to Russian involvement since Russians love to visit the cathedral city in Wiltshire, but the ticket was dated 2018 and bought with a senior discount railcard which is not available to Russian citizens.

And further confirmation that it might be the Russians comes from the fact that there are no flights to Russia from Heathrow, due to the Ukraine war, so while this chaos disrupts travel to many other destinations it does not affect travellers to Russia because there are none.