There is a gridsquare (T)C at the top of this British topo sheet of Iraq, the (T)C square covers Basra.
https://nla.gov.au/nla.obj-233334852/view
and the same grid on this sheet
https://nla.gov.au/nla.obj-233336193/view
Iran-Iraq 1:500,000 [cartographic material] : Basra.
nla.gov.au
Brendan Whyte
National Library of Australia
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