It had roots in a 1930s informal oppositional group within the Norwegian labour movement. The informal group was led by Håkon Meyer, and was more radical than the mainstream labour movement. On 9 April 1940 Germany invaded Norway, and subsequently occupied the country. The mainstream labour movement was now engaged in fighting and opposing a German rule. However, the grouping around Håkon Meyer wanted to steer the labour movement in another direction; taking advantage of the occupation to make conditions for laborers more favourable. The grouping was soon supported by some members of the radical Communist Party of Norway, and by non-partisan trade unionists such as Halvard Olsen.