Sir; At the Oxford Farming Conference I was disapointed to see that both David Miliband and David Cameron have dodged the need to break the supermarket armlock on farmers. Without the necessary political will for a legally binding supermarket code of conduct to stop them exploiting farmers, the Competition Commision inquiry could be toothless.

A fair deal from supermarkets and making the most of the opportunities that climate change presents will improve the viability of farming. However we cannot lose sight of the importance of maintaining food security.

When it comes to Cameron's calls for more accurate labelling of British produce, his policy of shaking up food packaging information is not a new idea - it is just mutton labelled as lamb.

Lib Dems have for many years highlighted the impact of growing supermarket dominance in the groceries market on competition and sustainable development. particularly in rural areas. As far back as 2004, we argued for loopholes in what could be ­labelled British to be closed.