* Priests say sponsorship makes church look privileged
* Advertising campaign backed by big brands
By Paul Day
MADRID, June 22 (Reuters) - A group of 120 Spanish Catholic priests have criticised church leaders for signing up a list of high-profile corporate sponsors for a visit by the Pope in August, saying authorities had given in to temptation.
In a rare joint letter, the priests told Archbishop of Madrid Cardinal Antonio Maria Rouco Varela the sponsorship deals reinforced the impression the church was a privileged institution.
"It's been necessary to form a pact with the economic and political powers which reinforces the image of the church as a privileged institution, close to power, and the social scandal this implies, especially in the context of the economic crisis," the priests said in an open letter.
Organisers of Pope Benedict's visit, scheduled for August 18-21 as part of the celebrations of World Youth Day, have mounted a nationwide advertising campaign, backed by well-known multinationals and Spain's top companies.
Corporate logos of the companies, including Coca Cola , Telefonica , Santander and Iberia , fill the sponsorship page of the official visit website www.madrid11.com/.
"To trust in the strength of power and money ... is to give in to a temptation as old as the Church," said the letter.
"No one can serve two masters. You cannot serve both God and money," the letter said, citing the passage from the Bible, Matthew 6:24.
The Archbishop declined to comment.
The 10-page open letter, posted on the "Priests of Madrid Forum" website earlier this week -- forocurasdemadrid.org/ -- also criticised at length some of the companies' roles in the economic crisis.
"The crisis has its origin in the banks' and large groups' uncontrolled desire for profits," the priests wrote.
"We believe the Cardinal, concerned about the multi-million budget for the event, has chosen the worst collaborators."
A visit by the head of the Catholic church to Britain was roundly criticised last year for its high cost to taxpayers, estimated at around 10 million pounds. (Reporting by Paul Day; Editing by Philippa Fletcher)