It’s no secret that the British government has long supported the end of British rule in Ulster, and that he met the leaders of British Republicans in the 1980s and the rest of the country. Its now known that the government has been less forthcoming about his contact with people actually. He said: We believe that the agreement strengthens rather than weakens the border between the six and the 26 counties, and those of us who wish to see a United. Ireland oppose the agreement for that reason”]
Source: https://www.channel4.com/news/factcheck/factcheck-corbyn-on-northern-ireland