Workers renovating a cellar in a building in Belgium have stumbled on a hidden treasure of gold worth an estimated £7.5million. 

The hoard was found as a firm worked on a former brewhouse in the town of Sint-Gillis-Dendermonde, about a 40-minute drive from Brussels, on Tuesday morning. 

The stash was hidden in a wall and contained gold bars, gold nuggets and a mountain of coins. 

It was unclear exactly how the treasure hoard was stored, with some reports describing a 'chest', while others saying it was wrapped in plastic.  

An 18-year-old student worker called Kobe found the stash as he and a colleague were working on sewage piping at around 8.15am. 

While excavating the wall, he initially came across the coins which he believed were just ordinary €1 coins. But upon finding the nuggets and bars, he realised he had stumbled upon something major. 

Upon finding the stash the contractors immediately called the client, a charity called CAW Oost-Vlaanderen, as well as the police. 

The stash has since been moved to a high-security vault belonging to the Belgian government.  

Police are now investigating the source of the treasure, as it is unclear how it ended up in the building. Many of the gold bars appear to have been stamped around 1957 and 1961.

Local police chief Patrick Feys said that people in the town descended on the site after news of the hoard spread. 

He called on potential prospectors to stay away from the location of the find: 'Be aware that this is a fenced construction site with several dangerous pits. 

'Moreover, we have already been there and everything is guaranteed to be gone. So definitely do not take any irresponsible risks.'

Geert Hillaert of CAW Oost-Vlaanderen told local media that it may be several years before the hoard's original owners are found. 

He said: 'First, it must be investigated to what extent the gold can be linked to criminal acts from the past. 

'In addition, it is being examined whether rightful owners can still be found in some way.'

It's not yet clear whether the charity or the construction firm will get anything for finding the treasure. 

Earlier this week, it was revealed that Britain abandoned its claim to a £5.5billion treasure from a Royal Navy shipwreck near Gibraltar over fears it would upset Spain.  

Leaked cables from the early 2000s show how ministers scrapped plans to rescue a warship understood to be HMS Sussex in case it would threaten relations with Spain, despite the UK owning the wreck.

HMS Sussex was a Royal Navy flagship lost off Gibraltar more than three centuries ago. It is believed the wreck sits in international waters to the east of Gibraltar, which Britain could claim under international maritime law.

The warship sank in a storm in 1694 while carrying up to ten tons of gold, records suggested, which would amount to £5.5billion today – making it the most lucrative shipwreck discovered.

In 2001, Odyssey Marine Exploration, the US deep sea exploration company, said it was '99 per cent' sure it had found the ship after a three-year search.

The UK government signed an agreement with the company in September 2002, agreeing to recover the wreck and for the sale of treasure to be split.

News of the contract sparked furore and incited diplomatic tensions with Spain, which said it owned the ship due to its position in claimed Spanish waters.

It emerged through once confidential diplomatic cables from the US that UK officials said the dispute was causing 'an unnecessary threat' to British-Spanish relations. 

In the documents, released by Wikileaks, Dame Denise Holt, then deputy head of mission at the British embassy in Madrid, said officials would seek to 'terminate' the contract with Odyssey.

She added in June 2007 the 'controversy' made the British embassy 'distance themselves as much as possible from Odyssey', and was also affecting 'Gibraltar issues'.

The Florida-based Odyssey would also, she said, lose British 'aid' when their ships sailed from the port of Gibraltar, where they were moored.

Meanwhile Carmen Calvo, Spain's culture minister, said in a separate cable dated November 2005 that Odyssey would look for HMS Sussex 'over her dead body'.