A group of bipartisan U.S. lawmakers are urging the head of the U.K.’s surveillance court to hold an open hearing into Apple’s anticipated challenge of an alleged secret U.K. government legal demand.

U.S. Senator Ron Wyden, along with four other federal lawmakers, said in a letter this week to the president of the U.K.’s Investigatory Powers Tribunal (IPT) that it is “in the public interest” that any hearings about the alleged order are not held in secret.

The lawmakers’ letter also says that the alleged U.K. order has barred California-based Apple from engaging in speech that is “constitutionally protected” under U.S. law, and impedes the lawmakers’ ability to conduct congressional oversight.

The Washington Post revealed in February that the U.K. government had earlier this year secretly ordered Apple to create a “backdoor,” allowing U.K. authorities to access the cloud-stored data of any Apple customer worldwide. Apple, which is legally barred from disclosing or commenting on the so-called “technical capabilities notice,” reportedly refused and pulled its Advanced Data Protection iCloud data-encryption feature from U.K. customers, rather than comply with the backdoor order.

The U.K.’s Investigatory Powers Tribunal, which hears legal cases related to the use of U.K. surveillance powers, is scheduled to hear a private petition on Friday, per the tribunal’s public schedule. The hearing reportedly relates to Apple, according to Wyden’s letter.

Apple did not comment when reached by TechCrunch on Friday.

The U.K. government has so far declined to comment on operational matters, which includes “confirming or denying the existence of any such notices,” per a spokesperson 

It’s not clear how many companies have received a technical demand from the U.K. government. 

According to the lawmakers’ letter, Google “also recently told Senator Wyden’s office that, if it had received a technical capabilities notice, it would be prohibited from disclosing that fact.” 

Two civil rights groups, Liberty and Privacy International, are also challenging the U.K. government’s backdoor order via legal submission to the IPT. The pair have also called for the oversight body’s hearing into Apple’s appeal to be held in public, joining similar calls earlier this week by privacy rights groups.