You will not be surprised to hear that I often get calls about leases. This one was interesting because Jag Sanghera, who runs DS News in London's Shepherd's Bush, has a high-profile landlord.

Not only do Land Securities have a sizeable piece of the new Westfield Centre, but they also own the 60 shops opposite, one of them being Jag's outlet.

Jag had a 15-year lease which expired in 2003. The property was acquired by Land Securities, but rather than renewing the lease it chose to send an invoice for the old amount every month, which Jag is paying promptly.

Then he heard two worrying rumours. One is that as various properties on either side of him fell empty Land Securities was planning redevelopment. The second was that he might be liable for backdated increases if the lease was renegotiated.

The advice from all the experts is to not wait for leases to expire in the first place. A lease is a two-way thing, giving you protection as well as the landlord.

The very first thing to do is read the lease. This will tell you when the expiry date is and whether or not you are entitled to a new lease under the provisions of the Landlord and Tenant Act 1954 (you and the landlord may have agreed at the beginning to exclude this right to renew).

For Jag's case, I consulted Andrew Wilby, chairman of the Yorkshire Independent Grocers Association and a chartered surveyor with business transfer agents Everett Mason & Furby Northeast.

He says: "If a landlord does nothing and the tenant remains in situ then the rent can't be put up, but if the landlord serves a Section 25 notice then negotiations must start again. Alternatively, the tenant can serve a Section 26 on the landlord which effectively invites him to offer new terms."

Andrew points out that one of the problems with not renewing leases is that the landlord can make you put the property into a good state of repair. If he is planning to knock it down though, he shouldn't force you to repair (although some will try).

It is a good idea to hire a chartered surveyor to negotiate new terms for you as they should be able to save you more than their fees. Andrew also recommends getting the legal fees in advance and going for a practice that specialises in the Landlord and Tenant Act.

Generally speaking, owing to the troubled property market, now is a good time to renegotiate rents and leases.