A trade union has said it is still “fighting to win the war” against outsourcing after it lost a High Court battle over the employment rights of outsourced workers at the University of London.

The Independent Workers Union of Great Britain (IWGB) took legal action in a bid to represent outsourced security guards, post room workers, audio-visual staff, porters and receptionists at the university.

The university has refused to recognise the IWGB for the purposes of collective bargaining, arguing that the workers are employed by a facilities management company, Cordant Security.

In January last year, the Central Arbitration Committee (CAC), a tribunal which considers union recognition and collective bargaining cases, rejected the IWGB’s application to represent Cordant employees as the company already had an agreement with another trade union, Unison.

The CAC also found that the University of London was not one of the outsourced workers’ employers.

Giving his judgment in London on Monday, Mr Justice Supperstone dismissed the IWGB’s challenge to the CAC’s decision.

He ruled that there had been “no interference” with the outsourced workers’ right to collective bargaining as the union was “free to seek voluntary collective bargaining arrangements with both Cordant and the university”.

The judge held that, even if there had been an interference with that right under Article 11 of the European Convention on Human Rights, any such interference was justified.

At a hearing in February, the IWGB claimed the University of London was “in reality” also the outsourced workers’ employer and that its members were being denied their human right to collective bargaining with their “de facto employer”.

But Mr Justice Supperstone said that “a de facto employer is not a known or recognised concept”.

He ruled: “I do not accept that Article 11 requires that the union should have a right of compulsory collective bargaining with the university, which is not the relevant workers’ employer and with whom they have no contract relationship.”

The judge added: “There are, in my view, relevant and sufficient reasons for limiting the right to compulsory collective bargaining to workers and their employers.

“The university has a right to arrange its operations in what it considers to be the most efficient and beneficial manner.

“Organisations are entitled to adopt outsourcing arrangements, should they wish to do so, as a legitimate means of organising their activities.”

In a statement after the ruling, IWGB general secretary Jason Moyer-Lee said: “The University of London, with considerable help from the Tory Government, may have won the battle.

“But when it comes to the exploitative, discriminatory and fundamentally unfair practice of outsourcing it is the war that the IWGB is fighting to win.

“Outsourced workers at the University of London and elsewhere will continue to fight in both the courts and in the workplace until they are brought in-house and treated equally with their directly employed colleagues.”

A University of London spokeswoman said: “We note the High Court’s judgment and its conclusion that the Central Arbitration Committee was correct in determining that the application of the Independent Workers Union of Great Britain for recognition by the University of London for collective bargaining in respect of a group of workers not employed by the university but by Cordant Security Ltd was inadmissible.

“We note that in reaching this conclusion the court determined that the legislation based on which the CAC made its decision was fully compatible with Article 11 of the European Convention on Human Rights.

“The university’s plans for bringing externally contracted services in-house progress to schedule.”

Before the hearing in February, the IWGB said victory could have extended “the rights of the UK’s 3.3 million outsourced workers” by introducing the concept of a joint-employer to English law.

The High Court hearing coincided with strikes at the University of London and two Government departments organised by the IWGB and fellow trade unions the United Voices of the World (UVW) and the Public and Commercial Services Union (PCS).

Around 200 outsourced workers and their supporters also held a march organised by the three unions which gathered outside the Royal Courts of Justice ahead of the hearing.