OUTSOURCED security guards at London’s Great Ormond Street Hospital launched historic six-week strike action alongside a race discrimination legal challenge today.

The industrial action, set to be the longest in NHS history, comes after the predominantly black and ethnic minority migrant workers complained of poorer pay and working conditions than their majority white in-house colleagues.

The strikes, organised by United Voices of the World (UVW), were postponed last week after the union said bosses at the world-famous children’s hospital had signalled they were considering improvements to working conditions.

The guards, who are also pursuing legal claims accusing the institution of indirect race discrimination under the Equality Act, are employed by Carlisle Support Services, a company owned by billionaire Tory donor Lord Ashcroft.

Ahead of Thursday’s rally outside the hospital, set to be addressed by former Labour leader Jeremy Corbyn, UVW general secretary Petros Elia described the workers’ treatment as “immoral.”

A hospital spokesperson claimed it was “committed to full-scale harmonisation of terms and conditions across all areas.”