A compound of formula I, wherein: T represents W represents O; V represents N; R 1 represents C 1-2 alkoxy or H; R 2 represents -NR A1 S 2 R B1, -S 1-2 R B2, -P R B3 R B4, -C NHR A2; R A1 and R A2 independently represent H or methyl optionally substituted by one or more halo substituents; R B1 to R B4 independently represent C 1-2 alkyl optionally substituted by one or more halo substituents; R 3 represents C 3-5 alkyl, C 3-6 alkynyl or trimethylsilyl; A represents CH or N; R 4 represents C 3-4 cycloalkoxy, ethynyl, cyano, halo, C 1-2 alkoxy or C 1-2 alkyl, which latter two groups are optionally substituted by one or more halo substituents; Q represents O, S p, SO 2 N(R 6) or C N; n represents 1, 2 or 3; p represents 0, 1 or 2; R 5a and R 5b independently represent H or methyl, or R 5a and R 5b together represent -(CH 2) 2-4 -; when n represents 1, Z represents O or, when n represents 2 or 3, Z represents either an O-atom on each occurrence, or an S-atom on one occurrence and an O-atom on each other occurrence; G represents -[(CH 2) r -Het 1] 0-1 -C 2 H or a carboxylic acid isostere; r represents 0 or, when Het 1 is attached to (CH 2) r via a ring heteroatom, r may alternatively represent 1; Het 1 represents a 5- or 6-membered heterocyclic group that is fully aromatic, which group contains one to three heteroatoms selected from N, O and S or a 5- or 6-membered heterocyclic group that is fully saturated or partially unsaturated, and is monocyclic or is fused or bridged bicyclic, which group contains one or two heteroatoms selected from N, O and S, wherein Het 1 is optionally substituted by one or more substituents selected from C 1-2 alkyl, hydroxyl and oxo, or a pharmaceutically acceptable salt, solvate or isotopic derivative thereof; and wherein the carboxylic acid isostere is: (a) tetrazolyl; (b) -C N -S 2 CH 3; (c) -C N -S 2 N(CH 3) 2; (d) or a tautomer thereof; (e) or a tautomer thereof. T represents W represents O; V represents N; R 1 represents C 1-2 alkoxy or H; R 2 represents -NR A1 S 2 R B1, -S 1-2 R B2, -P R B3 R B4, -C NHR A2; R A1 and R A2 independently represent H or methyl optionally substituted by one or more halo substituents; R B1 to R B4 independently represent C 1-2 alkyl optionally substituted by one or more halo substituents; R 3 represents C 3-5 alkyl, C 3-6 alkynyl or trimethylsilyl; A represents CH or N; R 4 represents C 3-4 cycloalkoxy, ethynyl, cyano, halo, C 1-2 alkoxy or C 1-2 alkyl, which latter two groups are optionally substituted by one or more halo substituents; Q represents O, S p, SO 2 N(R 6) or C N; n represents 1, 2 or 3; p represents 0, 1 or 2; R 5a and R 5b independently represent H or methyl, or R 5a and R 5b together represent -(CH 2) 2-4 -; when n represents 1, Z represents O or, when n represents 2 or 3, Z represents either an O-atom on each occurrence, or an S-atom on one occurrence and an O-atom on each other occurrence; an O-atom on each occurrence, or an S-atom on one occurrence and an O-atom on each other occurrence; G represents -[(CH 2) r -Het 1] 0-1 -C 2 H or a carboxylic acid isostere; r represents 0 or, when Het 1 is attached to (CH 2) r via a ring heteroatom, r may alternatively represent 1; Het 1 represents a 5- or 6-membered heterocyclic group that is fully aromatic, which group contains one to three heteroatoms selected from N, O and S or a 5- or 6-membered heterocyclic group that is fully saturated or partially unsaturated, and is monocyclic or is fused or bridged bicyclic, which group contains one or two heteroatoms selected from N, O and S, a 5- or 6-membered heterocyclic group that is fully aromatic, which group contains one to three heteroatoms selected from N, O and S or a 5- or 6-membered heterocyclic group that is fully saturated or partially unsaturated, and is monocyclic or is fused or bridged bicyclic, which group contains one or two heteroatoms selected from N, O and S, wherein Het 1 is optionally substituted by one or more substituents selected from C 1-2 alkyl, hydroxyl and oxo, or a pharmaceutically acceptable salt, solvate or isotopic derivative thereof; and wherein the carboxylic acid isostere is: (a) tetrazolyl; (b) -C N -S 2 CH 3; (c) -C N -S 2 N(CH 3) 2; (d) or a tautomer thereof; (e) or a tautomer thereof. (a) tetrazolyl; (b) -C N -S 2 CH 3; (c) -C N -S 2 N(CH 3) 2; (d) or a tautomer thereof; (e) or a tautomer thereof.