Liquid variable in ParcelForce tracking URL

Hi there,

I am trying to get the below tracking reference into the URL for ParcelForce tracking site to use on the order confirmation Email (this email template has been customised from the standard order confirmation template).

I have this URL:

https://www.parcelforce.com/track-trace?trackNumber=

I have tried with the {{ tracking_number }} variable but it doesn’t pull anything through.

https://www.parcelforce.com/track-trace?trackNumber={{ tracking_number }}

I have looked at other variables including this one but it pulls through the wrong reference number

https://www.parcelforce.com/track-trace?trackNumber={{ fulfillment.tracking_number }}

My question what is the variable I should be using?

Hii Harry

{{ tracking_number }} is not working

can you please tell me code for this one ?

Thanks Harry