This is how accurate they are (you don’t normally get a pulse per second link from a hosting company in the UK even if you use NPL as your main NTP server_
vfr@*******l:~$ ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*ntp.nmi.nl .PPS. 1 u 49 1024 377 3.314 -0.375 0.242
-dg010.tilaa.nl 193.79.237.14 2 u 595 1024 377 1.325 -0.171 0.121
+bandersnatch.ro 85.12.29.43 3 u 267 1024 377 1.710 -0.415 0.340
+metronoom.dmz.c .PPS. 1 u 837 1024 377 1.779 -0.379 0.211
-europium.canoni 193.79.237.14 2 u 1017 1024 377 9.501 -2.078 0.399
vfr@******:~$ ntptime
ntp_gettime() returns code 0 (OK)
time d62207c6.324d098c Mon, Nov 4 2013 12:47:18.196, (.196488972),
maximum error 44541 us, estimated error 88 us, TAI offset 0
ntp_adjtime() returns code 0 (OK)
modes 0x0 (),
offset -375.100 us, frequency -0.046 ppm, interval 1 s,
maximum error 44541 us, estimated error 88 us,]
status 0x6001 (PLL,NANO,MODE),
time constant 10, precision 0.001 us, tolerance 500 ppm,
vfr@*******:~$
