The news that Royal Mail have joined the 10:10 climate change campaign has been welcomed by its staff. But questions over the company's commitment have bubbled to the surface.

The Communication Workers Union has called its targets to reduce carbon emissions into question. As a major employer, it has one of the biggest fleets in Europe – and it has plans to bring in 24,000 new vehicles next year according to Union bosses. In some cases, even replacing bicycles or walking deliveries.

10:10 is a climate change campaign that aims to get individuals and companies to reduce their carbon footprint by 10 per cent during 2010.

It's another public blow for the national postal service, as strikes continue to disrupt mail services all this week. Today will see walkouts across London.