Is comma before 'and even' needed?

Consider the following sentence:

Many businesses in the service sector, such as banks and insurance companies(,) and even telecommunication companies, use software intensively.

In British English, is the comma before 'even' above forbidden, optional, or mandatory? Or is there a difference in the meaning depending on whether you use it or not? Please assume that we use the serial (Oxford) comma in the enclosing text. If there are some errors in a sentence, please improve them in any case. Explanations with references are welcome.


Solution 1:

In answering this, I realized that the entire middle part of the sentence is, itself, parenthetical, regardless of the nature of and even telecommunication companies. Since it is, those comma pairs need to remain no matter what.

The essential sentence is simply:

Many businesses in the service sector use software intensively.


Either and even telecommunication companies is parenthetical to the two list items that precede it or it is a third list item.

Depending on the intended meaning, the punctuation will vary.


Parenthetical

Here is what the sentence would look like using actual parentheses, as well as what it would look like with the parenthetical information removed:

Many businesses in the service sector, such as banks and insurance companies (and even telecommunication companies) use software intensively.

→ Many businesses in the service sector, such as banks and insurance companies, use software intensively.

Given this interpretation, it would look like this with commas rather than parentheses:

  1. Many businesses in the service sector, such as banks and insurance companies, and even telecommunication companies, use software intensively.

A Third List Item

  1. Many businesses in the service sector, such as banks, insurance companies, and even telecommunication companies, use software intensively.