I welcome your leader criticising the decision by the NUJ to boycott Israeli goods (April 20). For many years we have been working with trade unions in the region, the Histadrut (Israeli TUC) and the Palestinian General Federation of Trade Unions (PGFTU), to meet and establish links with British unions. What trade unionists need in the region is solidarity, engagement and respect, not divisive calls that can only help the extremists. The general secretary of the PGFTU said in a letter only this week to Ofer Eini, chairman of the Histadrut, that "we must emphasise our mutual need for peace in our two societies, for the benefit both of workers and because peace will reflect stability". If the two union federations want to work for peace together it is our duty to support them. It is a pity that the NUJ did not take part in our recent delegation to the region to show real solidarity with fellow trade unionists, rather than taking on gesture politics.Chair, Trade Union Friends of Israel

You suggest that, in voting to boycott Israel, the NUJ has strayed too far from its legitimate business. We do not think such arguments apply to our grave concerns as doctors about the health-related impact of Israeli policy on Palestinian society. Persistent violations of medical ethics have accompanied Israel's occupation. The Israeli Defence Force has systematically flouted the fourth Geneva convention guaranteeing a civilian population unfettered access to medical services and immunity for medical staff. Ambulances are fired on (hundreds of cases) and their personnel killed. Desperately ill people, and newborn babies, die at checkpoints because soldiers bar the way to hospital. The public-health infrastructure, including water and electricity supplies, is wilfully bombed, and the passage of essential medicines like anti-cancer drugs and kidney dialysis fluids blocked. In the West Bank, the apartheid wall has destroyed any coherence in the primary health system. UN rapporteurs have described Gaza as a humanitarian catastrophe, with 25% of children clinically malnourished.

The Israeli Medical Association has a duty to protest about war crimes of this kind, but has refused to do so. Appeals to the World Medical Association and the British Medical Association have also been rebuffed. Eighteen leading Palestinian health organisations have appealled to fellow professionals abroad to recognise how the IMA has forfeited its right to membership of the international medical community. We are calling for a boycott of the Israeli Medical Association and its expulsion from the WMA. There is a precedent for this: the expulsion of the Medical Association of South Africa during the apartheid era. A boycott is an ethical and moral imperative when conventional channels do not function, for otherwise we are merely turning away.

Dr Derek Summerfield, Professor Colin Green, Dr Ghada Karmi, Dr David Halpin, Dr Pauline Cutting And 125 other doctors