Britain has warned that Iranian plans to build new uranium enrichment plants are a matter of serious concern and would breach UN Security Council resolutions.<br/><br/>A Foreign Office spokeswoman said, Britain will consider its response in partnership with the UN watchdog the International Atomic Energy Agency IAEA and others. <br/><br/>A defiant Iranian government led by President Mahmoud Ahmadinejad vowed on Sunday to build 10 new uranium enrichment plants and also study a plan to process the material to 20 per cent purity. <br/><br/>The move comes after the IAEA condemned Iran for building a second enrichment plant near the Shiite holy city of Qom, and asked for its construction to stop.<br/>