Dated updated:

Much around teacher flexibility will fall to the specifics of what is in the contract of employment (or what can be inferred by ‘custom and practice’).

Full-time teachers on ‘standard’ national terms must be available to perform such duties at such times and such places as may be specified by the headteacher for 1,265 hours (1,258.5 hours for the school year beginning in 2021 due to the Queen’s Platinum Jubilee), those hours to be allocated reasonably throughout those days in the school year on which the teacher is required to be available for work. 

Planning, preparation and assessment also needs to be factored in to that time and shouldn’t be less than 10 per cent of the teacher’s timetabled teaching time.

The 1,265 hours need to be carried out during the 195 days (195 for the 2021 year) that a full-time teacher must be available for during the school year. 190 days of that can be teaching, five days must be days when the employer can require the teacher to do other duties, but not teaching. 

So there is some limited flexibility to ask teachers to carry out tutoring duties within that standard framework although not much, and individuals may argue that if they have always worked a certain pattern, to change it would be a change to their contract.  There have been some recent figures thrown around which indicate that teachers work an average of 45 hours a week anyway (ie far in excess of the above) so to ask them to do more needs to be handled very sensitively.

If there is a clause in the contract which imposes an obligation on the employee to work such additional hours as are necessary for the full/proper performance of their duties then an employer may be able to rely on this to ask the employee to do more, but expect to be met with resistance and union representation.
Senior leaders are not subject to the same limits as above, and are paid on a leadership scale, so schools might be able to appeal to SLT members to take up some of the burden of tutoring. 

With either category of employee, schools need to be alert to the nominal cap on a working week under the Working Time Regs of 48 hours per week, averaged over 17 weeks. If employees are willing to do more hours they may need to implement an opt-out for this provision – depending of course on how many more hours are likely. 

The newly issued School Teachers Pay and Conditions Document 2021 – applicable from September 2021 – indicates at Para 53 of Section 3 - that the use of TLR3 payments may be an appropriate way to reward and remunerate teachers carrying out additional planning, preparation, coordination of, or delivery of tutoring to provide catch-up support to pupils on learning lost to the pandemic, and where that tutoring work is taking place outside of normal directed hours but during the school day. 

In my view, this makes it slightly more difficult to provide an accurate reward as it will not necessarily be a direct correlation between additional hours/workload and tutoring output. Nor does it recognise that not all days/weeks will be the same re tutoring time obligations. 

That said, it does allow schools to rely on the STPCD guidance which should help avoid some disputes and it may be that a ‘mini benchmarking’ is carried out pretty quickly to give schools some comfort of the level of TLR3 to offer. 

TLR3 can be offered to senior leaders as well.

A different option may be to create a separate ‘job’ for tutoring with its own identified duties, pay and specific contract. This would allow both employee and employer to be clear on the boundaries and responsibilities of the role. 
Just to supplement the ‘mini benchmarking’ – the STPCD does give some additional guidance on the parameters of a payment, but where the needle will fall in that bracket is less clear and up to employers to determine.