School teachers across Britain staged a national strike Wednesday against excessive workload, unwanted pay system and "unfair" pension arrangement, disrupting thousands of schools in the country. The one-day strike, staged by members of the National Union of Teachers (NUT), aimed to protest against excessive workload, a tougher performance related pay system and "unfair" pension arrangements, according to the NUT. Marches and rallies were held in more than 30 cities across England and Wales, including London, Bristol, Leeds, Oxford, Cambridge, Birmingham, Southampton, Manchester, Liverpool, Newcastle, and Cardiff and so on. Thousands of schools in England and Wales were completely or partially closed Wednesday, as NUT members took to the streets, waved placards, and chanted slogans to call for better government treatment over teachers' pay, pensions and conditions. "Today has been a clear demonstration that teachers are thoroughly tired of the intolerable pressures they are being put under by the coalition government," said Christine Blower, General Secretary of the NUT. "Teachers love teaching but are crushed by the long hours and stifling accountability regime," he added, stressing that the government is ruining teaching and education by turning a blind eye to teachers' concerns. "As a matter of urgency the government needs to address the real concerns of teachers by engaging seriously in the talks with the NUT and other teacher unions," he urged, warning to stage further strike action this summer if there is no progress in the talks. Citing government surveys, Blower said earlier this month that primary school teachers in the country work nearly 60 hours a week and secondary school teachers work nearly 56 hours a week, and two in five teachers are leaving the profession in the first five years of teaching. He said that government policies to change a national pay framework into a performance based pay system will build "unfairness and additional bureaucracy" for schools. The union leader also called for a "decent standard of living in retirement" for British teachers, for fear that the teachers' pensions could be squeezed under current government policies. In a letter to the NUT on Tuesday, British Secretary of State for Education Michael Gove said the direction of policy on pay and pensions is "fixed" following full consultation, and government-union negotiations should focus on the "implementation" of the fixed policy, prompting further dissatisfaction from the NUT members. The NUT, with more than 326,000 members, is one of the biggest teachers' unions in Britain