<Tr> <Td> Poland </Td> <Td> 7005312683000000000 ♠ 312,683 </Td> <Td> 38,224,410 </Td> <Td> 16 April 2003 </Td> <Td> 21 December 2007 </Td> </Tr> <Tr> <Td> Portugal </Td> <Td> 7004923910000000000 ♠ 92,391 </Td> <Td> 10,371,627 </Td> <Td> 25 June 1991 </Td> <Td> 26 March 1995 </Td> </Tr> <Tr> <Td> Slovakia </Td> <Td> 7004490370000000000 ♠ 49,037 </Td> <Td> 5,444,218 </Td> <Td> 16 April 2003 </Td> <Td> 21 December 2007 </Td> </Tr> <Tr> <Td> Slovenia </Td> <Td> 7004202730000000000 ♠ 20,273 </Td> <Td> 2,077,862 </Td> <Td> 16 April 2003 </Td> <Td> 21 December 2007 </Td> </Tr>

Why did the uk not sign the schengen agreement