What is the most stunning riverside in London to visit this summer? 

I am searching for a peaceful place in London with a panoramic view of the riverside. I have kids and we'd like to enjoy a memorable picnic with sufficient services before I go abroad for business trip. 

If you are looking for a good riverside in London to relax with the family, then I will suggest the following places:

Southbank

Ok not so relaxing as it is in the middle of the city, but the views are great and there are restaurants and art galleries and a carnival atmosphere most days, so a great place to take the kids I would say!

Camden Town

Not a river, but a canal goes through there. It can get very busy and touristy, but it is also a very entertaining place.

Hammersmith Bridge

This area has some nice restaurants and cafes by the river you can enjoy.

Chelsea embankment

Nice river, quiet and leafy part of town.

To be honest though, if you want somewhere quiet and by a large body of water, then why not go to Hampstead Heath or Hyde park on a sunny day... They have "ponds" rather than rivers... But it is very beautiful!