What's the current weight of the UK in the Commonwealth?

Last Tuesday, Pink News had a number of questions (reader submitted) thrown at PM Gordon Brown of the United Kingdom. The full interview can be read here. Anyway I'd remark one of the answers given by Brown, in regards to him having

announced an international strategy to promote (LGBT) rights overseas, which includes Britain's commitment to the universal decriminalization of homosexuality...

I'm not much informed on how the Commonwealth works, though I believe that such community includes former colonial territories of the British Empire, including Canada and Australia. The logical approach for a British government willing to deal with homophobia decriminalization of homosexuality in areas such as the West Indies and West and East Africa, India and Sri Lanka (anyone knows which countries in the Commonwealth, apart of the former three, have not laws against homosexuality?) would probably imply joining Canada and Australia into a lobbying politics. But to which extent would all three, or merely a single one of those countries (and in Australia there continues to happen some differences from state to state in terms of lgbt rights) could influence the rest of nations inside the Commonwealth?

The UK couldn't do much about challenging Akinola and the rest of Nigerian power players on the bill (full text here) they were to pass (which calls for a five-year imprisonment of people who engage "performs, witnesses, aids, or abets" a same-sex marriage, also of anyone involved in advocacy for gay and lesbian rights.

So what could be expectable from PM Gordon Brown? I honestly hope that it's something more than wishful thinking.