ChD 23 January 1990. A lease dated 25 October 1974, for a term of fourteen years, included an option to renew for a further fourteen years at a "fair and reasonable market rent ...". Clause 6 provided that any dispute be referred to arbitration . The arbiter held in the landlords favour but the tenant was given leave to appeal. The first issue was whether the new rent was to be determined on the objective criteria of what a hypothetical willing landlord and tenant would agree as the market rent , as the tenant contended, or by subjective criteria of what would be fair and reasonable for the parties themselves to agree. It was held in favour of the tenant. The second issue was whether the landlord was entitled to discovery of the tenants profit and loss accounting for the last six years. It was held that if the rent was to be determined by objective criteria the trading accounts would be inadmissable in evidence .