Teachers in three states in Nigeria are on strike this week because their governments have failed to pay out agreed pay rises.Teachers in Lagos, Osun and Oyo states went on strike last Wednesday. The teachers are members of the Nigerian National Union of Teachers (NUT) which reached agreement with the employers after a strike last summer for a 27.5% pay rise. When three of the states failed to keep to the agreement union leaders gave them three weeks to honour their side of the bargain. When no new money was forthcoming the teachers went on strike. The state governments are blaming the economic crisis for their failure to pay although other poorer states are honouring the agreement.The highest paid teachers in Nigeria only earn about $100 a month.