There is no automatic entitlement to such benefits. They are between you and your employer, so any scheme should normally be referred to in your contract of employment – or perhaps in a staff handbook – as an express term. Alternatively it may sometimes be possible to establish an entitlement by virtue of custom and practice.
Your employer must not breach equality laws when offering access to these facilities and should make them available to everyone equally.
If these benefits are available to full-time workers, they should also be offered to comparable part-time workers unless the employer has a good objective reason for treating part-time workers differently.
The provision of some of these benefits may be considered by HM Revenue and Customs to be a taxable benefit. Further advice should be obtained from your local tax office.
If you are an agency worker, and these benefits are being offered to comparable direct employees of the hirer where you work, you may have a legal basis under the Agency Workers Regulations 2010 for arguing that they should also be offered to you. Speak to your union rep.