Convert local time string to UTC

[madasafish]

I am using gawk version 4.0.0 and reading a file that has local time strings in two of the CSV fields and would like to convert these strings to UTC time strings.
This is a monthly exercise and local time will automatically change depending on the time of the year.

$ date
Sat Apr  6 09:55:30 BST 2013

$INFILE with local time strings

05:30:00,22:00:00
19:00:00,07:00:00
19:00:00,06:00:00

As always, thanks in advance.

Madasafish

 

[madasafish]

I forgot to mention the converted UTC Time strings should be in the same format as the local time strings supplied.
Many thanks,
Madasafish