Is foreign aid by Britain a waste of time?

Is the British foreign trade a waste of time? For instance, would it not be more beneficial to open up our markets to African farmers, so that they would get better prices for their products? Apparently, we are subsidising farm production in Malawi, which is just distorting things.
We send aid to India and in return Indian companies come over and buy up firms
such as Tetley Tea. Perhaps we could persuade the companies to do more to counter rural poverty, which is immense in India.
Unhappily, our aid programmes seem to tie in with political/economic objectives such as selling products these countries do not need. www.searchaccountant.co.uk although we are not as brazen as the Chinese selling arms to Zimbabwe.
With New Labour our foreign aid efforts have included some right-on programmes in Afghanistan about gender, which must have perplexed the locals.