Unless there is an express term in the contract of employment for your employer to require you to work from home, such a change would be a unilateral variation of contract, altering your work location, which you do not have to accept.
Browse our section on Working from Home for information about the general issues you should consider with your employer when considering this sort of arrangement.
If there is a specific requirement from your employer for you to work at home and you have no alternative but to do so, you may be able to get tax relief on some of your household expenses. The kinds of expenses that you can claim includes the additional cost of gas and electricity used during the period you work from home, plus the cost of any business calls not reimbursed by your employer.
HM Revenue and Customs have agreed a flat rate expense of £4 a week, which can be claimed for any week you are required to work from home.
If your expenses are greater than this and you wish to claim a greater amount you will need to show HMRC how you have worked out the figure of expenses you are claiming. There are details on tax relief for employees working from home on the GOV.UK website.
There may be Capital Gains Tax implications when you come to sell your home if part of the house was used exclusively for business purposes. This is a complex area of taxation. The GOV.UK website has some detail on taxation on property and rental income.