Just checked my Aircraft Radio License (Wireless Telegraphy Act 2006) and Certificate of Approval of Aircraft Radio Installation issued by UK CAA and aside from standard stuff ATC Transponder, DME and VHF COMM/NAV it states:
“ The licensee also authorises the use of Aeronautical VHF Hand portable radio equipment operating in the frequency band 118-137 MHz …. for use on the above named aircraft”
I have found an ICOM linked to a headset an absolute necessity when sometimes waiting upwards of 20 minutes on a ground frequency - for start approval.