Sir – Colin Cook presents us with a choice between sacrificing some of the Green Belt and losing open spaces within the city’s boundaries.

Does he assume that Oxford can go on expanding indefinitely? We have to face the fact that endless growth is neither possible nor desirable.

If the University cannot accommodate its graduate students without resorting to developments such as Castle Mill, it should stop accepting increasing numbers of such students. And, at a national level, we need to have policies to halt the growth in population.

Simon Mollison, Oxford