Do UK citizens need proof of onward travel when entering peru and not returning to the UK for more than 90 day

i am heading to south america for 6 months and enter in peru, hence to the peruvian immigration i will be there for more than 90 days without a visa. is it necessary to prove to immigration that you will be leaving the country in less than 90 days i.e. with another flight ticket?

Usually peruvian migration officers are very helpful. You do not need to "prove" that you will be leaving the country in 90 days.At the entrance port, you will receive a permit for 3 months and then you will have to renew the permt for another 3 months.
Enjoy Peru!

Thank you for the selection! By the way, you have to go to Inmigration Offices to renew the permit. Bon voyage Report It

According to http://www.delta.com/planning_reservatio...

National UNITED KINGDOM (GREAT BRITAIN)
Destination PERU

Passport required (recommended to be valid at least 6 months on arrival).

Visa not required for a max. stay of 90 days, for touristic purposes only 30 day extensions possible (max. 3 extensions) by applying with the Peruvian Immigration Authorities. Fee: USD 20.-.

If travelling for business purposes: visa required.

However, visa not required if holding an APEC (see Terms and Definitions) Business Travel Card, provided the back of the card states that it is valid for travel to Peru.

Visitor must hold ticket and all documents required for
return/onward journey. Visitor not holding return/onward
tickets must buy one or will be deported.

Nope, they welcome gringos who want to spend money here.