Brazil I believe - page 11 of document here here and you'll probably find the whole document helpful if you are genuinely interested.
India is also looking at doing something unilaterally, see here and has also been leading the push for this to become a global system. As well as going alone what Labour has done is pledge to work with countries seeking to make such changes rather than seek to block on the justification of (false) self-interest.
I’ll admit that I wouldn’t want a Corbyn/McDonnell overall majority. As someone who believes in mixed/capitalist economics, I do believe in justice and fairness, including in taxation, and have done so long before it became trendy. Often overlooked, tax swerving multinationals gain a huge competitive advantage over competitors paying their full whack of UK corporation tax on profits. Helping Amazon and Starbucks, as two obvious examples, over high street competitors. I’d love something serious done to tackle this cheating.