Teachers are due to walk out on Wednesday in the first national strike in more than six years. As schools and the government prepare, here鈥檚 what you need to know about developments this week. Over 30k join NEU before strikes Since the vote to strike, around 32,000 people have joined the National Education Union – and the vast majority are teachers. Strike rules mean anyone who is an NEU member by the time of the action can go on strike. As can school staff who do not belong to a union. However staff in unions that failed in strike votes cannot join industrial action. The NEU said the growth in members “should worry the government. Our argument is cutting through”. 鈥楧on鈥檛 pressure staff to cross picket lines鈥 Staff should not be put under pressure to work on strike days or to cross picket lines, the NAHT and National Education Union (NEU) have told their members in a call for unity. Teachers are under 鈥渘o obligation鈥 to provide advance notice that they plan to strike, and the unions have agreed that 鈥渟chool leaders will not put staff under pressure to do so鈥, joint guidance says. However, it is 鈥渁lso recognised that school leaders have a duty to carry out a risk assessment in advance to assess whether a school can be kept open or partially open鈥. 鈥淲e jointly agree that no pressure should be placed on staff to attend work on a strike day or to cross a picket line.鈥 The guidance followed reports of rising tensions between teachers and leaders. Support staff union clashes with DfE over cover Unison, which represents more than 200,000 support staff in England鈥檚 schools, has that seemingly clashes with advice from the DfE. The union鈥檚 members should 鈥渃ontinue with their normal duties鈥, but should 鈥渘ot take on any additional responsibilities being given to them directly as a result of other unions鈥 industrial action鈥. Support staff 鈥渟hould not be expected to provide cover for, or take classes, where this would normally be done by teachers who are taking action鈥, the union said. But in its guidance the DfE said that schools could use support staff 鈥渢o provide cover supervision or oversee alternative activities鈥. 鈥淪upport staff are able to carry out ‘specified work’ provided they are subject to the direction and supervision of a qualified teacher.鈥 Ofsted U-turns on strike day inspections Schools will not be inspected on days when teachers are due to go on strike. Previous guidance stated that strikes would be treated similarly to other disruption. Inspectors would 鈥渢ake a view as to whether there is sufficient activity taking place to enable it to conduct an inspection鈥, and 鈥渓ikely鈥 defer if there wasn鈥檛. But Ofsted said this week it would schedule inspections and notifications of inspections to avoid strike days in February. The policy will be reviewed ahead of further planned walkouts in March. On the days where strikes are limited to certain regions, inspections will continue as normal elsewhere. NAHT will re-ballot its members The NAHT school leaders鈥 union will re-ballot its members for industrial action, its leader confirmed this week, after its previous vote failed to reach the turnout threshold. The organisation said last week that it was considering going back to its membership after just 42 per cent of eligible members voted in its last ballot, short of the 50 per cent required by law. On Wednesday Paul Whiteman, its general secretary, confirmed the union was 鈥渃ommitted to balloting again鈥, although it would wait until talks with the government either ended or broke down. The union also this week criticised a DfE request to heads for information on whether their schools would open on strike days. Whiteman said heads were unlikely to know the impact of the walkouts at this stage. Keegan challenges NEU over strike vote Gillian Keegan, the education secretary, has questioned the NEU over the timing of its announcement of its strike ballot and how it informed schools. Keegan asked the union to clarify when employers were told about the results, which were announced to members and the wider public at 5pm last Monday during a live Facebook event. The union said it had informed the DfE of the results 鈥渟hortly before 5pm鈥 on January 16, and the department 鈥渢hen informed schools (and hence employers) that the ballot results would lead to strike action鈥 in a post on its Education Hub blog. It then wrote to 鈥渁ll relevant employers鈥 the following day.