A compound, wherein the compound is either a compound of the formula: or a salt thereof, wherein: p is 0, 1 or 2; q is 1 or 2; r is 1 or 2; s is 1 or 2, where the total of r and s is 2 or 3; X is C or N; Z is CH 2 or O; Y is O or CH 2; R 1 is H, halo, CN, OH, C 1-3 alkoxy, NH 2, optionally substituted C 1-6 alkyl, optionally substituted C 2-6 alkenyl, optionally substituted C 2-6 alkynyl, optionally substituted C 3-6 cycloalkyl, optionally substituted C 3-6 cycloalkenyl, wherein the optional substituents are one to six fluorine atoms and wherein one or two, but not all of the carbon atoms may optionally be replaced by a heteroatom selected from O, N and S and oxidised forms thereof, NR 5 R 6, COOR 5, CONR 5 R 6, NR 7 CONR 5 R 6, NR 7 COOR 5, OCONR 5 R 6, SR 5, SOR 5, SO 2 R 5; SO 3 R 5, W or CH 2 -W where W is a 5 or 6 membered cycloalkyl, heterocycloalkyl, aryl or heteroaryl ring; R 2 is H, halo, CN, OH, C 1-3 alkoxy, NH 2, optionally substituted C 1-6 alkyl, optionally substituted C 2-6 alkenyl, optionally substituted C 2-6 alkynyl, optionally substituted C 3-6 cycloalkyl, optionally substituted C 3-6 cycloalkenyl, wherein the optional substituents are one to six fluorine atoms and wherein one or two, but not all of the carbon atoms may optionally be replaced by a heteroatom selected from O, N and S and oxidised forms thereof, NR 5 R 6, COOR 5, CONR 5 R 6, NR 7 CONR 5 R 6, NR 7 COOR 5, OCONR 5 R 6, SR 5, SOR 5, SO 2 R 5; W or CH 2 -W where W is a 5 or 6 membered cycloalkyl, heterocycloalkyl, aryl or heteroaryl ring, or R 1 and R 2 together form a cycloalkyl ring optionally incorporating a maximum of 2 heteroatoms selected from O, S or N, and optionally substituted by a maximum of 6 atoms of F; R 3 is H, optionally substituted C 1-6 alkyl, optionally substituted C 2-6 alkenyl, optionally substituted C 2-6 alkynyl, optionally substituted C 3-6 cycloalkyl, optionally substituted C 3-6 cycloalkenyl, wherein the optional substituents are one to six fluorine atoms and wherein one or two, but not all of the carbon atoms may optionally be replaced by a heteroatom selected from O, N and S and oxidised forms thereof, W or CH 2 -W where W is a 5 or 6 membered cycloalkyl, heterocycloalkyl, aryl or heteroaryl ring; or R 3 and R 2 together form a cycloalkyl or heterocycloalkyl ring; R 4 is H or an acyclic C 1-4 hydrocarbon group optionally substituted with one or more fluorine atoms; and R 5, R 6 and R 7 are independently H or C 1-6 alkyl; or is selected from: methyl 2-(2-oxo-1,3,8-triazaspiro[4.5]dec-8-yl)-6-azaspiro[3.4]octane-6-carboxylate; ethyl 2-(2-oxo-1,3,8-triazaspiro[4.5]dec-8-yl)-6-azaspiro[3.4]octane-6-carboxylate; or a salt thereof. p is 0, 1 or 2; q is 1 or 2; r is 1 or 2; s is 1 or 2, where the total of r and s is 2 or 3; X is C or N; Z is CH 2 or O; Y is O or CH 2; R 1 is H, halo, CN, OH, C 1-3 alkoxy, NH 2, optionally substituted C 1-6 alkyl, optionally substituted C 2-6 alkenyl, optionally substituted C 2-6 alkynyl, optionally substituted C 3-6 cycloalkyl, optionally substituted C 3-6 cycloalkenyl, wherein the optional substituents are one to six fluorine atoms and wherein one or two, but not all of the carbon atoms may optionally be replaced by a heteroatom selected from O, N and S and oxidised forms thereof, NR 5 R 6, COOR 5, CONR 5 R 6, NR 7 CONR 5 R 6, NR 7 COOR 5, OCONR 5 R 6, SR 5, SOR 5, SO 2 R 5; SO 3 R 5, W or CH 2 -W where W is a 5 or 6 membered cycloalkyl, heterocycloalkyl, aryl or heteroaryl ring; R 2 is H, halo, CN, OH, C 1-3 alkoxy, NH 2, optionally substituted C 1-6 alkyl, optionally substituted C 2-6 alkenyl, optionally substituted C 2-6 alkynyl, optionally substituted C 3-6 cycloalkyl, optionally substituted C 3-6 cycloalkenyl, wherein the optional substituents are one to six fluorine atoms and wherein one or two, but not all of the carbon atoms may optionally be replaced by a heteroatom selected from O, N and S and oxidised forms thereof, NR 5 R 6, COOR 5, CONR 5 R 6, NR 7 CONR 5 R 6, NR 7 COOR 5, OCONR 5 R 6, SR 5, SOR 5, SO 2 R 5; W or CH 2 -W where W is a 5 or 6 membered cycloalkyl, heterocycloalkyl, aryl or heteroaryl ring, or R 1 and R 2 together form a cycloalkyl ring optionally incorporating a maximum of 2 heteroatoms selected from O, S or N, and optionally substituted by a maximum of 6 atoms of F; R 3 is H, optionally substituted C 1-6 alkyl, optionally substituted C 2-6 alkenyl, optionally substituted C 2-6 alkynyl, optionally substituted C 3-6 cycloalkyl, optionally substituted C 3-6 cycloalkenyl, wherein the optional substituents are one to six fluorine atoms and wherein one or two, but not all of the carbon atoms may optionally be replaced by a heteroatom selected from O, N and S and oxidised forms thereof, W or CH 2 -W where W is a 5 or 6 membered cycloalkyl, heterocycloalkyl, aryl or heteroaryl ring; or R 3 and R 2 together form a cycloalkyl or heterocycloalkyl ring; R 4 is H or an acyclic C 1-4 hydrocarbon group optionally substituted with one or more fluorine atoms; and R 5, R 6 and R 7 are independently H or C 1-6 alkyl; or is selected from: methyl 2-(2-oxo-1,3,8-triazaspiro[4.5]dec-8-yl)-6-azaspiro[3.4]octane-6-carboxylate; ethyl 2-(2-oxo-1,3,8-triazaspiro[4.5]dec-8-yl)-6-azaspiro[3.4]octane-6-carboxylate; methyl 2-(2-oxo-1,3,8-triazaspiro[4.5]dec-8-yl)-6-azaspiro[3.4]octane-6-carboxylate; ethyl 2-(2-oxo-1,3,8-triazaspiro[4.5]dec-8-yl)-6-azaspiro[3.4]octane-6-carboxylate;