A compound of formula: a tautomer thereof, or a pharmaceutically acceptable salt of said compound or tautomer, wherein: R 1b, R 1c, R 1d, R 1e each independently represent hydrogen or C 1 -C 6 alkyl; R 1a and R 1g each independently represent hydrogen, fluorine, cyano, hydroxyl, amino, C 1 -C 6 alkyl, or C 1 -C 6 alkoxy; R 1f represents hydrogen, fluorine, cyano, hydroxyl, amino, C 1 -C 6 alkyl, or C 1 -C 6 alkoxy, or R 1f together with R 2 forms a 5-membered heterocyclic ring; R 2 represents hydrogen or C 1 -C 6 alkyl, or R 2 together with R 1f forms a 5-membered heterocyclic ring; X is C(R 3)(R 4), wherein R 3 and R 4 each independently represent hydrogen, cyano or C 1 -C 6 alkyl; L represents a covalent bond, -SO-, -SO 2 -, -C -, -C O-, -CONR 5 -, -SO 2 NR 5 -, -C -C 1 -C 6 alkylene, -C -C 2 -C 6 alkenylene, C 1 -C 6 alkylene-C -, C 1 -C 6 alkylene, or -C 2 -C 6 alkenylene; A represents a substituted 5 to 10-membered monocyclic, heteroaryl or aryl ring, or an optionally substituted 9 to 10-membered bicyclic, heteroaryl or aryl ring; R 5 represents hydrogen or C 1 -C 6 alkyl; wherein ring A, when substituted, is substituted with one to four -Q 1 -(R 6) n, wherein each occurrence of -Q 1 -(R 6) n is the same or different; n is 0 or 1; Q 1 represents halogen, cyano, oxo, nitro, -OR 7, -SR 7, -NR 7 R 8, -CONR 7 R 8, -NR 7 COR 8, - NR 7 CONR 8 R 9, -COR 7, -C OR 7, -NR 7 C OR 8, -C 1 -C 6 alkyl, -C 1 -C 6 alkoxy, a covalent bond, an oxygen atom, a sulphur atom, C 1 -C 6 alkylene, or -C 2 -C 6 alkenylene; R 6 is a 3 to 10-membered heterocyclyl, cycloalkyl, heteroaryl, or aryl ring; R 7, R 8 and R 9 each independently represent hydrogen, C 1 -C 6 alkyl, or C 1 -C 6 alkylene; wherein R 6 is optionally substituted with one to four substituents, each independently selected from halogen, cyano, oxo, nitro, -OR 10, -SR 10, -NR 10 R 11, -C 1 -C 6 alkyl, and -C 1 -C 6 alkoxy; R 10 and R 11 each independently represent hydrogen or C 1 -C 6 alkyl; wherein the heterocyclic ring formed by R 1f together with R 2 is optionally further substituted with oxo; and wherein said C 1 -C 6 alkyl and C 1 -C 6 alkoxy are each independently optionally substituted with one to four substituents, each independently selected from halogen, hydroxyl, thiol, cyano, amino, nitro, and SF 5. R 1b, R 1c, R 1d, R 1e each independently represent hydrogen or C 1 -C 6 alkyl; R 1a and R 1g each independently represent hydrogen, fluorine, cyano, hydroxyl, amino, C 1 -C 6 alkyl, or C 1 -C 6 alkoxy; R 1f represents hydrogen, fluorine, cyano, hydroxyl, amino, C 1 -C 6 alkyl, or C 1 -C 6 alkoxy, or R 1f together with R 2 forms a 5-membered heterocyclic ring; R 2 represents hydrogen or C 1 -C 6 alkyl, or R 2 together with R 1f forms a 5-membered heterocyclic ring; X is C(R 3)(R 4), wherein R 3 and R 4 each independently represent hydrogen, cyano or C 1 -C 6 alkyl; L represents a covalent bond, -SO-, -SO 2 -, -C -, -C O-, -CONR 5 -, -SO 2 NR 5 -, -C -C 1 -C 6 alkylene, -C -C 2 -C 6 alkenylene, C 1 -C 6 alkylene-C -, C 1 -C 6 alkylene, or -C 2 -C 6 alkenylene; A represents a substituted 5 to 10-membered monocyclic, heteroaryl or aryl ring, or an optionally substituted 9 to 10-membered bicyclic, heteroaryl or aryl ring; R 5 represents hydrogen or C 1 -C 6 alkyl; wherein ring A, when substituted, is substituted with one to four -Q 1 -(R 6) n, wherein each occurrence of -Q 1 -(R 6) n is the same or different; n is 0 or 1; Q 1 represents halogen, cyano, oxo, nitro, -OR 7, -SR 7, -NR 7 R 8, -CONR 7 R 8, -NR 7 COR 8, - NR 7 CONR 8 R 9, -COR 7, -C OR 7, -NR 7 C OR 8, -C 1 -C 6 alkyl, -C 1 -C 6 alkoxy, a covalent bond, an oxygen atom, a sulphur atom, C 1 -C 6 alkylene, or -C 2 -C 6 alkenylene; R 6 is a 3 to 10-membered heterocyclyl, cycloalkyl, heteroaryl, or aryl ring; R 7, R 8 and R 9 each independently represent hydrogen, C 1 -C 6 alkyl, or C 1 -C 6 alkylene; wherein R 6 is optionally substituted with one to four substituents, each independently selected from halogen, cyano, oxo, nitro, -OR 10, -SR 10, -NR 10 R 11, -C 1 -C 6 alkyl, and -C 1 -C 6 alkoxy; R 10 and R 11 each independently represent hydrogen or C 1 -C 6 alkyl; wherein the heterocyclic ring formed by R 1f together with R 2 is optionally further substituted with oxo; and wherein said C 1 -C 6 alkyl and C 1 -C 6 alkoxy are each independently optionally substituted with one to four substituents, each independently selected from halogen, hydroxyl, thiol, cyano, amino, nitro, and SF 5.