Withdrawing a dismissal
Q: Following negotiations on job cuts, one of our members was issued with a written notice that their employment would be terminated. The employer has now said it is withdrawing the notice. Can it do this unilaterally?
A: There is a principle that, once notice has been given, it cannot be withdrawn without the other party's agreement. This has been applied in cases such as Riordan v War Office [1959] 3 All ER 552, where the High Court said that notice "could not be withdrawn save with the mutual consent" of the employer and employee.
Case law has not always followed this principle - the EAT held in the case of Martin v Yeoman Aggregate Ltd [1983] IRLR 49 that a dismissal or resignation taking place "in the heat of the moment" can be withdrawn unilaterally, as long as this happens almost immediately once tempers have cooled. (In that particular case, the employee had a row with the company director and was told to go, but five minutes later the director came back and said he was not dismissed. The EAT said he had not been dismissed and so could not claim unfair dismissal.)
However, this "heat of the moment" scenario clearly does not apply in your case.