One of the world’s largest projects for scientific co-operation, the Cern laboratory in Geneva, has become embroiled in a divisive row over homophobia.

The European particle physics laboratory has garnered international fame for its work at the Large Hadron Collider, a vast underground circular tunnel where, in 2012, scientists used a particle accelerator to prove the existence of the sub-atomic Higgs boson particle.

However, its reputation as a co-operative community of scientists from all over the world has been dealt a blow after allegations emerged that a spate of homophobic incidents had taken place at the laboratory.

At least one researcher is reported by The Sunday Times to have been formally disciplined after CCTV cameras caught them defacing posters advertising Cern’s Lesbian, Gay, Bisexual and Transgender (LGBT) club events.

LGBT Cern group members claim the abuse has been ongoing for years, with posters defaced with words such as “Schwein” (German for pig) and Old Testament biblical quotations describing sexual relations between men as an “abomination” for which they should be “put to death”.

“The continuing defacing of our posters is an unacceptable campaign of hate and intolerance,” British physicist and founder of LGBT Cern group Aidan Randle-Conde told the newspaper. “We do keep a track of how many posters get taken down or defaced and over a two-week period roughly one-third can be removed. I don’t know who is responsible, although it is probably the work of a few people. In some cases there have been religious texts attached to the posters.”

Hadron Collider sets collision record Show all 9 1 /9 Hadron Collider sets collision record Hadron Collider sets collision record Two beams of protons began 10 days ago to speed at high energy in opposite directions around the 27-kilometer (17-mile) tunnel under the Swiss-French border at Geneva. Hadron Collider sets collision record Emeritus professor at the University of Edinburgh, British Peter Higgs is seen inside the Large Hadron Collider (LHC) tunnel. Higgs is best known for his theory explaining the origin of mass of elementary particles in general and the Higgs Boson in particular. It is anticipated that the LHC will determine the existence of the Higgs Boson. Getty Images Hadron Collider sets collision record A model of the Large Hadron Collider (LHC) tunnel is seen in the CERN (European Organization For Nuclear Research) visitors' centerin Geneva-Meyrin, Switzerland. CERN is building the world's biggest and most powerful particle accelerator. The LHC is installed in a tunnel buried 50 - 150 m below ground. Getty Images Hadron Collider sets collision record A woman passes behind a layers of the world's largest superconducting solenoid magnet (CMS), one of the experiments preparing to take data at European Organization for Nuclear Research (CERN)'s Large Hadron Collider (LHC) particule accelerator. Getty Images Hadron Collider sets collision record A European Organization for Nuclear Research (CERN) scientist checks a monitor at the Alice experiment control room Getty Images Hadron Collider sets collision record An engineer pointing to the magnet core of the world's largest superconducting solenoid magnet (CMS, Compact Muon Solenoid). Getty Images Hadron Collider sets collision record Belgium's King Albert II (3rd R) visits the Large Hadron Collider of the European Organization for Nuclear Research CERN (Centre Europeen de Recherche Nucleaire) in Geneva. Getty Images Hadron Collider sets collision record Technicians work at the building of the cap of the Large Hadron Collider. Some 2000 scientists from 155 institutes in 36 countries are working together to build the CMS particle detector. Getty Images Hadron Collider sets collision record Rolf-Dieter Heuer, who is to become the director of CERN, with a giant photograph of the CMS detector of the Large Hadron Collider (LHC) at the "Weltmaschine "("World Machine") exhibition in Berlin, Germany. Getty Images

The abuse became so bad last year that Cern’s then director-general Rolf-Dieter Heuer warned all staff that they would be “dealt with accordingly” if there were further “acts of defacement to the LGBT community’s posters”.

Despite the warning, problems appear to have continued and last month Cern’s director of human resources issued a second caution to all staff.

A recent blog posted by the LGBT Cern group marking its fifth anniversary also referred to the problem on site. It read: “In a lab of thousands of people from all over the world and of all ages, it is not surprising to find a small minority who have a problem with our group.

“They have always been at the lab; the difference is that now they are making themselves known.”

A spokesman for Cern told The Sunday Times: “Cern really cannot accept something like this and it is why we have taken disciplinary measures against at least one person we could identify as being responsible for these disrespectful actions. Homophobic behaviour is not and will not be tolerated at Cern.”

Both Cern and LGBT Cern were unavailable for comment when contacted by The Independent on 20 March.

Cern, the European Organisation for Nuclear Research, was created in 1954 on the Franco-Swiss border to investigate the basic structure of the universe by studying what makes up matter.

The laboratory now has more than 10,000 scientists and engineers from 21 countries working on the project. One of the most significant by-products of its work has been the creation of the world wide web by the British scientist Sir Tim Berners-Lee.

A spokesperson for CERN said: "CERN considers that these acts are unacceptable, and strongly condemned on various occasions. This is in our DNA not only words, and is clearly reflected in our core values and in our code of conduct. Homophobic behaviour is clearly not welcome at CERN and will not be tolerated."