Change the DELETE item in VOC to a new name, like DELETE.HIDE.
Create a VOC item named DELETE, but it is a paragraph that calls a UniBasic program.
Inside the UniBasic program, validate as necessary, such as checking @LEVEL.  You can add tracking/logging as you desire.  If the delete is allowed, EXECUTE/PERFORM the renamed DELETE item in the VOC (e.g. DELETE.HIDE) using the file and item information from @PARASENTENCE.   Be certain to account for active select lists.

Dean thanks for that information
 Have never used @LEVEL where can I find more information about it
in the Unibasic documentation all it says is - "Current PERFORM or EXECUTE level"

Robert,

Here is my worked example showing the difference on testing @LEVEL to allow / disallow an EXECUTE / PEFORM DELETE in UniBasic.

Write a subroutine called DELETESEC as below

SUBROUTINE DELETESEC(OKAY)
OKAY = 0
RETURN
END

Compile and Catalog

Copy the DELETE verb from the VOC to your alternative VOC (in my case SECVOC)

Case 1 from ECL (Note DELETE is not a verb)

:DELETE VOC XX
Not a verb
 DELETE
:

Case 2 from Basic using the following program (Note XX gets deleted via the Basic DELETE command)
AE BP DEL.XX
Top of "DEL.XX" in "BP", 9 lines, 157 characters.
*--: p
001: OPEN "VOC" TO F.VOC ELSE STOP
002: WRITE "XX" TO F.VOC,"XX"
003: DELETE F.VOC,"XX"
004: READ DUMMY FROM F.VOC,"XX" THEN
005:   CRT "ON FILE"
006: END ELSE
007:   CRT "NOT ON FILE"
008: END
009: END
Bottom.
*--: fibr
Filed "DEL.XX" in file "BP" unchanged.

Compiling Unibasic: BP\\DEL.XX in mode 'u'.
compilation finished
NOT ON FILE
:

Case 3 EXECUTE / PERFORM from Basic (Not the EXECUTE of DELETE is blocked)
AE BP DEL.XX.2
Top of "DEL.XX.2" in "BP", 2 lines, 27 characters.
*--: P
001: OPEN "VOC" TO F.VOC ELSE STOP
002: WRITE "XX" TO F.VOC,"XX"
003: EXECUTE 'DELETE VOC XX'
004: END
Bottom.
*--: FIBR
Filed "DEL.XX.2" in file "BP" unchanged.

Compiling Unibasic: BP\\DEL.XX.2 in mode 'u'.
compilation finished
In BP\\_DEL.XX.2 at line 3 Not a verb
In BP\\_DEL.XX.2 at line 3  DELETE
:

Now if you wish allow the EXECUTE 'DELETE' change the program DELETESEC to read
@LEVEL contains the number of EXECUTE / PERFORM levels you have gone down.
The initial level is 0.

SUBROUTINE DELETESEC(OKAY)
IF @LEVEL NE 0 THEN OKAY = 1 ELSE OKAY = 0
RETURN
END

Compile and recatalog as required

From ECL (Note still blocked from ECL)

:DELETE VOC XX 
Not a verb
 DELETE
:

Use First Program (DELETE command from UniBasic works)
:RUN BP DEL.XX
NOT ON FILE
:

Use Second Program Now (The EXECUTE DELETE is allowed)
:RUN BP DEL.XX.2
'XX' deleted.

If you where to test @SENTENCE in DELETESEC when using DEL.XX.2 it would contain 'DELETE VOC XX' 
@PARASENTENCE would be set if coming from a paragraph.

Hope this explains it all

------------------------------
Jonathan Smith
UniData ATS
Rocket Support
------------------------------

Jonathan thanks for that additional information
so if someone tries to uses delete from the command prompt then @level will equal 0
and if a basic program executes delete then @level will equal 1