Most employers include some sort of flexibility in contracts of employment which allow them to adapt their business as things change. This flexibility may allow for an adjustment to your hours of work, shift pattern, or work location.
There are a set of principles that define the distance and time duration that your employer believes to be normally reasonable. This is up to 25 miles, or a journey time from home to work of 1 hour and 15 minutes.
However, what is reasonable may vary between individuals, geographical locations, modes of transport and other situations. What the business believe may be reasonable, may not, in fact, be reasonable to you. Your individual circumstances must be considered, including the impact to any personal or caring responsibilities that you may have outside of work.
Any location move can be on a temporary or permanent basis.
Expenses & travel allowances:
If you do make a long term or permanent move to your base location at your employer's request, and this lengthens your commute by 10 miles or more, or an additional 30 minute travel time, your employer will pay your travel expenses. This is called a travel allowance.
Travel allowances compensate you through an additional allowance, payable monthly along with your normal salary. They are payable for up to 12 months after the move has occurred. In exceptional circumstances, your employer may agree to review this and extend this period.
Where travel allowances are payable, you are being compensated for the additional expenses that you incur, and these will need to be calculated. For example, if you normally walk to work and the requested move requires you to travel by car then your travel allowance would cover the cost of your travel using the applicable mileage rates, and any parking. In another example, if you currently pay for parking and the cost of parking is the same in your new location, then you wouldn't be paid the cost of parking as there is no detriment to you.
Where you are asked to travel away from your base work location to another location - for example to support another work location for a day, week, or month - and this increases your travel costs, these should be paid through the normal expenses policy. Travel allowance is only paid on longer term periods of relocation.
Your employer should give you as much notice of a proposed change in work location as possible, however as a minimum, at least two weeks notice of a permanent move to a new work location must be given.