When Wim Kok Lamont said the text was not negotiable .
Wim Kok is the Dutch finance minister chairing the finance ministers ' negotiations at Maastricht decided that the meeting should review the British opt - out line - by - line .
When Wim Kok , the Dutch finance minister chairing the finance ministers ' negotiations at Maastricht decided that the meeting should review the British opt - out line - by - line , Lamont said the text was not negotiable .