Generally speaking, provisions of a staff handbook are deliberately couched in terms that they do not form part of the employment contract, the main reason being that it is desirable for an employer to be flexible in its application of policy and procedures and be permitted to change them from time to time as suits them.
Where there is a dispute as to whether the terms are or can be incorporated into an individual's employment contract will be resolved by reference to the precise terms of the particular documents in each case.
Such an issue came before the Court of Appeal in the case of Department of Transport v Sparks & Ors  EWCA Civ 360 of whether the provisions contained in a staff handbook found in various versions of the same, were "legally enforceable contractual terms or were mere notes of guidance and good practice of no legal force".
There was provision in the contract about the handbook as follows:- "The Department Staff Handbook, as applying to you, sets out many of your terms and conditions. It is the intention of the recognised trade unions ... and the Crown that all of the provisions of the handbook which apply to you and are apt for incorporation should be incorporated into your contract of employment".
The provision of the handbook included trigger points in relation to sickness absence which would require some action on the part of the employer. The question at first instance was whether a later change to those provisions could be enforceable against the employee or whether they amounted to a unilateral change of terms by the employer, which would not be permitted.
Having considered previous authority on the question of incorporation of terms in the cases of Wandsworth LBC v D'Silva  IRLR 193 and Keeley v Fosroc International Ltd. EWCA Civ 1277, the Court of Appeal agreed with the Employment Judge at first instance that the provisions of the Handbook had been incorporated into the employees contracts.
Clearly it is important to be clear in the wording of any staff handbook or contract where there is reference to the handbook in order to perhaps avoid such issues.
It was noted that the Department for Transport was criticised by the Court as "not satisfactory for the employer and the employee alike" that previous versions of the staff handbook, which was in electronic form, had been amended at various times and it was extremely difficult to ascertain which was the correct version of the particular clauses, essentially because previous versions had been deleted and no record kept of the previous ones.
Lesson to us all - keep previous versions of your staff handbook!