Leaked photos show the squalid conditions endured by soldiers who protect King Charles - described as being 'worse than prison'.
The prestigious Wellington barracks, just 300 yards from Buckingham Palace, houses an estimated 500 service personnel from The Coldstream, Grenadier, Irish, Scots and Welsh Guards.
But the candid snaps revealed piles of rubbish, clogged and filthy toilets, mouldy fridges and leaky appliances.
A dead bird is also seen, having been left to rot on a stairwell.
Those stationed there - often seen standing guard outside Buckingham Palace and St James' Palace dressed in full military regalia - have protected the Sovereign and Royal Palaces since 1660.
A Coldstream Guard said it was a "disgusting" way to treat soldiers "doing a very important job".
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He recently quit the regiment due to the living conditions.
The soldier - who wished to remain anonymous - described rats in the bins and the smell from the toilets being "unbearable".
It's understood 32 privates live on each floor, sharing six toilets and two bathrooms.
Those stationed at the barracks played a key role in Operation London Bridge - the funeral plan for Queen Elizabeth II.
Hundreds of soldiers marched in the procession last September.
The eight pallbearers from the Queen's Company, 1st Battalion Grenadier Guards, also stayed at the Wellington barracks the night before.
The former Coldstream Guard told MailOnline that inmates in Britain's prisons "have better living conditions than we do".
He said: "Wellington Barracks is absolutely filthy but from the outside they look great. Tourists stand at the gates to take pictures, but they wouldn’t believe what life is like for soldiers inside.
"The rats would die in the bins, and we’d have to clean them out when doing block jobs in the morning. There are piles of rubbish inside the accommodation areas and the stench from the toilets is unbearable. All the problems are in the blocks where the privates live.
"I can promise you this would not happen in the officers' block. I couldn’t take it anymore, it was worse than living in a filthy squat. I put up with it for several years, but nothing changed. The British public needs to know how soldiers in this country are treated."
Another soldier claimed the squalid conditions were raised with senior officers, but privates were ignored or told to "f*** off".
He added that they were "treated like scum".
One of the soldiers spoken to said he received a salary of £22,000 a year working in the regiment, and earned double that now in the security industry.
It comes after Amey, the Ministry of Defence's maintenance contractor was found earlier this year to have missed 10,535 urgent repair appointments since last April.
Fellow contractor Vivo missed 4,041.
Other data showed more than 44,000 Armed Forces personnel were housed in 'Grade 4' accommodation in 2021, the MOD's lowest rating score.
A Ministry of Defence spokesperson told the Mirror: “The provision of good quality, secure accommodation for Service Personnel is a key priority.
"While 95% of this type of accommodation meets the Decent Homes Standard, we are spending more than £1.6 billion over the next decade to make improvements and build new living quarters.”
They added the Defence Accommodation Strategy introduces the Defence Minimum Standard (DMS) for SLA, ensuring that by 2030 all SLA will be fit for purpose and of a quality our Service Personnel deserve.
Buckingham Palace did not wish to comment.
